Communications Network

Special Tool(s)

	Fluke 77-IV Digital Multimeter FLU77-4 or equivalent
	Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool
	Flex Probe Kit NUD105-R025D or equivalent

Principles of Operation

Both High Speed Controller Area Network (HS-CAN) and Medium Speed Controller Area Network (MS-CAN) use an unshielded twisted pair cable of data (+) and data (-) circuits. The HS-CAN operates at a maximum data transfer speed of 500 Kbps and designed for real-time information transfer and control. The MS-CAN operates at a maximum data transfer speed of 125 Kbps for bus messages and is designed for general information transfer.

Controller Area Network (CAN) Fault Tolerance

NOTE: The oscilloscope traces below are from the Integrated Diagnostic System (IDS) oscilloscope taken using the IDS pre-configured CAN settings. The traces are for both data (+) and data (-) taken simultaneously (2-channel) at a sample rate of 1 mega-sample per second (1MS/s) or greater.

Traces below are viewed at 500mV per division (vertical axis) and 20 microseconds (20μs) per division (horizontal axis). Readings taken with a different oscilloscope vary from those shown. Compare any suspect readings to a known good vehicle.

Normal CAN Operation

The data (+) and data (-) circuits are each regulated to approximately 2.5 volts during neutral or rested network traffic. As messages are sent on the data (+) circuit, voltage is increased by approximately 1.0 volt. Inversely, the data (-) circuit is reduced by approximately 1.0 volt when a message is sent.

Successful communication of a message can usually be identified by the slight spike at the end of a message transmission. Any signals that are significantly different than the normal CAN waveform may cause network DTCs (U-codes) to set or may cause a complete network outage.

CAN Circuits Shorted Together

In the event the data (+) and data (-) circuits become shorted together, the signal stays at base voltage (2.5V) continuously and all communication capabilities are lost.

CAN (+) Circuit Shorted To Ground

In the event the data (+) circuit becomes shorted to ground, both the data (+) and data (-) circuits are pulled low (0V) and all communication capabilities are lost.

CAN (-) Circuit Shorted To Ground

In the event the data (-) circuit becomes shorted to ground, the data (-) circuit is pulled low (0V) and the data (+) circuit reaches near-normal peak voltage (3.0V) during communication but falls to 0V instead of normal base voltage (2.5V). Communication may continue but at a degraded level.

CAN (+) Circuit Shorted To Battery Voltage

In the event the data (+) circuit becomes shorted to battery voltage, the data (+) circuit is pulled high (12V) and the data (-) circuit falls to abnormally high voltage (above 5V) during communication and reaches battery voltage (12V) for peak voltage. Communication may continue but at a degraded level.

CAN (-) Circuit Shorted To Battery Voltage

In the event the data (-) circuit becomes shorted to battery voltage, both the data (+) and data (-) circuits are pulled high (12V) and all communication capabilities are lost.

CAN Circuit Signal Corruption

Rhythmic oscillations, inductive spikes or random interference can disrupt the network communications. The corruption signal source may be outside electrical interference such as motors or solenoids or internal interference generated from a module on the network. In some cases, an open in either the data (+) or data (-) circuit to a network module may cause the module to emit interference on the one circuit which is still connected. The trace shown is an example of a "sawtooth" pattern transmitted from a module with one open network circuit.

Other corruptions may be present when a module is intermittently powered up and down. The module on power up may initiate communication out of sync with other modules on the network causing momentary communication outages.

Controller Area Network (CAN) Multiplex Messages

Modules on the CAN utilize simultaneous communication of two or more messages on the same network circuits. The following chart summarizes the messages sent and received on the network.

  CAN Module Communication Message Chart

NOTE: This chart describes the specific High Speed Controller Area Network (HS-CAN) and Medium Speed Controller Area Network (MS-CAN) messages broadcast by each module, and the module(s) that receive the message.

Inspection and Verification

1. Verify the customer concern.

2. Visually inspect for obvious signs of electrical damage.
   • If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

  Visual Inspection Chart

3. Connect the scan tool to the DLC .

   • NOTE: Make sure to use the latest scan tool software release.

     NOTE: The Vehicle Communication Module (VCM) LED prove-out confirms power and ground from the DLC are provided to the VCM .

     If the Integrated Diagnostic System (IDS) does not communicate with the VCM :
     • Check the VCM connection to the vehicle.
     • Check the scan tool connection to the VCM .
     • GO to Pinpoint Test S , to diagnose No Power To The Scan Tool.

4. Establish a scan tool session.

   • NOTE: The scan tool first attempts to communicate with the PCM, after establishing communication with the PCM, the scan tool then attempts to communicate with all other modules on the vehicle.

     If an IDS session cannot be established with the vehicle, ( IDS may state "No communication can be established with the PCM"):
     • Choose "NO" when the scan tool prompts whether or not to retry communication.
     • Enter either a PCM part number, tear tag or calibration number to identify the vehicle and start a session (the PCM part number and 4-character tear tag are printed on the PCM label).
     • GO to Pinpoint Test A , to diagnose The PCM Does Not Respond To The Scan Tool.

5. Carry out the network test.
   • If the network test passes, retrieve and record the continuous memory DTCs and proceed to Step 6.
   • If the network test fails, GO to Symptom Chart to diagnose the failed communication network.
   • If a module fails to communicate during the network test, GO to Symptom Chart .

6. Retrieve and review the DTCs.
   • If the DTCs retrieved are related to the concern, go to DTC Charts. Follow the non-network DTC diagnostics (B-codes, C-codes, P-codes) prior to the network DTC diagnostics (U-codes). For all other DTCs, refer to the Diagnostic Trouble Code (DTC) Chart in Section 419-10 .
   • If no DTCs related to the concern are retrieved, GO to Symptom Chart .

DTC Charts

NOTE: Network DTCs (U-codes) are often a result of intermittent concerns such as faulty wiring or low battery voltage occurrences. Additionally, vehicle service procedures such as module reprogramming will often set network DTCs. Replacing a module to resolve a network DTC is unlikely to resolve the concern. To prevent repeat network DTC concerns, inspect all network wiring, especially connectors. Test the vehicle battery, refer to Section 414-01 .

 Communication Network DTC Chart

NOTE: DTC U1900 will set in a module that is reporting a communication fault from another module on the data bus. The module that reports the fault is not the problem module.

Symptom Chart

Pinpoint Tests

Pinpoint Test A: The PCM Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 24 , Electronic Engine Controls - 5.0L for schematic and connector information.

Refer to Wiring Diagrams Cell 25 , Electronic Engine Controls - 5.8L for schematic and connector information.

Refer to Wiring Diagrams Cell 26 , Electronic Engine Controls - 3.7L for schematic and connector information.

Normal Operation

The PCM communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following:

• Wiring, terminals or connectors
• PCM

PINPOINT TEST A: THE PCM DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test B: The ABS Module Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 42 , Vehicle Dynamic Systems for schematic and connector information.

Normal Operation

The ABS module communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• ABS module

PINPOINT TEST B: THE ABS MODULE DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test C: The Instrument Panel Cluster (IPC) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 60 , Instrument Cluster for schematic and connector information.

Normal Operation

The Instrument Panel Cluster (IPC) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN) and the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse(s)
• Wiring, terminals or connectors
• IPC

PINPOINT TEST C: THE IPC DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test D: The Restraints Control Module (RCM) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 46 , Supplemental Restraint System for schematic and connector information.

Normal Operation

The Restraints Control Module (RCM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• Case ground open
• RCM

PINPOINT TEST D: THE RCM DOES NOT RESPOND TO THE SCAN TOOL

 WARNING: Never disassemble or tamper with seat belt deployable components, including pretensioners, load limiters and inflators. Never back probe deployable device electrical connectors. Tampering or back probing may cause an accidental deployment and result in personal injury or death.

 WARNING: Never probe the electrical connectors on airbag, Safety Canopy or side air curtain assemblies. Failure to follow this instruction may result in the accidental deployment of these assemblies, which increases the risk of serious personal injury or death.

NOTE: The Supplemental Restraint System (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.

NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test E: The Occupant Classification System Module (OCSM) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 46 , Supplemental Restraint System for schematic and connector information.

Normal Operation

The Occupant Classification System Module (OCSM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• OCSM

PINPOINT TEST E: THE OCSM DOES NOT RESPOND TO THE SCAN TOOL

 WARNING: Never disassemble or tamper with seat belt deployable components, including pretensioners, load limiters and inflators. Never back probe deployable device electrical connectors. Tampering or back probing may cause an accidental deployment and result in personal injury or death.

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: The Supplemental Restraint System (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.

NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test F: The Smart Junction Box (SJB) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 13 , Power Distribution/SJB for schematic and connector information.

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Normal Operation

The Smart Junction Box (SJB) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• SJB

PINPOINT TEST F: THE SJB DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test G: The Body Control Module B (BCM-B) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 89 , Interior Lamps for schematic and connector information.

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Normal Operation

The Body Control Module B (BCM-B) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• BCM-B

PINPOINT TEST G: THE BCM-B DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test H: The HVAC Module Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 54 , Manual Climate Control for schematic and connector information.

Refer to Wiring Diagrams Cell 55 , Automatic Climate Control System for schematic and connector information.

Normal Operation

The HVAC module communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• HVAC module

PINPOINT TEST H: THE HVAC MODULE DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test I: The Audio Front Control Module (ACM) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 130 , Audio System/Navigation for schematic and connector information.

Normal Operation

The Audio Front Control Module (ACM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• ACM

PINPOINT TEST I: THE ACM DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test J: The Front Controls Interface Module (FCIM) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 130 , Audio System/Navigation for schematic and connector information.

Normal Operation

The Front Controls Interface Module (FCIM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• FCIM

PINPOINT TEST J: THE FCIM DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test K: The Front Display Interface Module (FDIM) Does Not Respond To The Scan Tool (Without Navigation)

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 130 , Audio System/Navigation for schematic and connector information.

Normal Operation

The Front Display Interface Module (FDIM) (without navigation) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• FDIM

PINPOINT TEST K: THE FDIM DOES NOT RESPOND TO THE SCAN TOOL (WITHOUT NAVIGATION)

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test L: The Global Positioning System Module (GPSM) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Lodule Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 130 , Audio System/Navigation for schematic and connector information.

Normal Operation

TheGlobal Positioning System Module (GPSM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• GPSM

PINPOINT TEST L: THE GPSM DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test M: The Accessory Protocol Interface Module (APIM) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 130 , Audio System/Navigation for schematic and connector information.

Normal Operation

The Accessory Protocol Interface Module (APIM) communicates with the scan tool and other modules through the Medium Speed Controller Area Network (MS-CAN) and also communicates with other modules on the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• APIM

PINPOINT TEST M: THE APIM DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test N: The Power Steering Control Module (PSCM) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 43 , Power Steering Controls for schematic and connector information.

Normal Operation

The Power Steering Control Module (PSCM) communicates with the scan tool and other modules through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• PSCM

PINPOINT TEST N: THE PSCM DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test O: The Parking Aid Module (PAM) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 131 , Parking Aid for schematic and connector information.

Normal Operation

The Parking Aid Module (PAM) communicates with the scan tool and other modules through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• PAM

PINPOINT TEST O: THE PAM DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test P: The Vehicle Dynamics Module (VDM) Does Not Respond To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 41 , Vehicle Dynamic Suspension for schematic and connector information.

Normal Operation

The VDM communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• VDM

PINPOINT TEST P: THE VDM DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test Q: No Medium Speed Controller Area Network (MS-CAN) Communication, All Modules Are Not Responding

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Normal Operation

The Medium Speed Controller Area Network (MS-CAN) uses an unshielded twisted pair cable, circuits VDB06 ( MS-CAN -) and VDB07 ( MS-CAN +).

NOTE: The Instrument Panel Cluster (IPC), while on the MS-CAN , communicates with the scan tool only on the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following:

• Wiring, terminals or connectors
• Audio Front Control Module (ACM)
• Accessory Protocol Interface Module (APIM) (if equipped)
• Body Control Module B (BCM-B)
• Front Controls Interface Module (FCIM)
• Front Display Interface Module (FDIM) (without navigation)
• Global Positioning System Module (GPSM)
• HVAC module
• Instrument Panel Cluster (IPC)
• Smart Junction Box (SJB)

PINPOINT TEST Q: NO MS-CAN COMMUNICATION, ALL MODULES ARE NOT RESPONDING

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the Pinpoint Test.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test R: No High Speed Controller Area Network (HS-CAN) Communication, All Modules Are Not Responding

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Refer to Wiring Diagrams Cell 24 , 5.0L for schematic and connector information.

Refer to Wiring Diagrams Cell 25 , 5.8L for schematic and connector information.

Refer to Wiring Diagrams Cell 26 , 3.7L for schematic and connector information.

Normal Operation

The High Speed Controller Area Network (HS-CAN) uses an unshielded twisted pair cable, circuits VDB04 ( HS-CAN +) and VDB05 ( HS-CAN -).

NOTE: The APIM , while on the HS-CAN , communicates with the scan tool only on the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• ABS module
• Accessory Protocol Interface Module (APIM) (if equipped)
• Engine temperature gauge (if equipped)
• Instrument Panel Cluster (IPC)
• Occupant Classification System Module (OCSM)
• Parking Aid Module (PAM)
• PCM
• Power Steering Control Module (PSCM)
• Restraints Control Module (RCM)
• Vehicle Dynamics Module (VDM) (GT500)

PINPOINT TEST R: NO HS-CAN COMMUNICATION, ALL MODULES ARE NOT RESPONDING

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .

Pinpoint Test S: No Power To The Scan Tool

Refer to Wiring Diagrams Cell 14 , Module Communications Network for schematic and connector information.

Normal Operation

The scan tool is connected to the Data Link Connector (DLC) to communicate with the High Speed Controller Area Network (HS-CAN) and Medium Speed Controller Area Network (MS-CAN).

A loss of ground or poor ground at the DLC may result in HS-CAN or MS-CAN faults while the scan tool is connected. This may cause multiple malfunction indicators to be on with the scan tool connected to the DLC .

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• Scan tool
• DLC

PINPOINT TEST S: NO POWER TO THE SCAN TOOL

NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to Section 414-01 .