Pinpoint Test A: The PCM Does Not Respond To The Scan Tool
Communications Network
Pinpoint Test A: The PCM Does Not Respond To The Scan Tool
Refer to Wiring Diagram Set 14, Module Communications Network for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 24, Electronic Engine Controls - 3.5L IVCT for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 25, Electronic Engine Controls - 3.5L GTDI for schematic and connector information. Diagrams By Number
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:
- Fuse
- 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 will result in false resistance readings.
NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the Pinpoint Test. Communications Network
A1 VERIFY WHETHER OTHER HS-CAN (High Speed Controller Area Network) MODULES PASS THE NETWORK TEST
- Enter the following diagnostic mode on the scan tool: Network Test.
- In the LH pane of the Integrated Diagnostic System (IDS) network test display screen, verify whether any HS-CAN (High Speed Controller Area Network) modules passed the network test.
Is the text "pass" or a DTC listed next to any of the following modules (if equipped): 4X4 control module, ABS module, APIM (Accessory Protocol Interface Module), C-CM (Cruise-Control Module), HUD (Head Up Display) module, IPC (Instrument Panel Cluster), OCSM (Occupant Classification System Module), PAM (Parking Aid Module), PCM, PSCM (Power Steering Control Module), RFA (Remote Function Actuator) module or RCM (Restraints Control Module)?
Yes
If "pass" or a DTC was listed next to the PCM, a network fault is not currently present. GO to Pinpoint Test AE to diagnose an intermittent HS-CAN (High Speed Controller Area Network) fault condition. Pinpoint Test AE: No Power To The Scan Tool
If "pass" or a DTC was listed next to one or more modules other than the PCM, GO to A2.
No
No modules are currently communicating on the HS-CAN (High Speed Controller Area Network). GO to Pinpoint Test AD to diagnose no HS-CAN (High Speed Controller Area Network) communication. Pinpoint Test AD: No Medium Speed Controller Area Network (MS-CAN) Communication, All Modules Are Not Responding
A2 COMPUTERS AND CONTROL SYSTEMS INFORMATION PINPOINT TEST QA VERIFICATION
- Verify that Computers and Control Systems Information pinpoint test QA has been carried out.
Has pinpoint test QA been carried out?
Yes
GO to A3.
No
REFER to Computers and Control Systems Information, Pinpoint Tests, pinpoint test QA to diagnose no communication with the PCM.
A3 CHECK THE HS-CAN (High Speed Controller Area Network) TERMINATION RESISTANCE
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Disconnect the scan tool from the DLC (Data Link Connector).
- Measure the resistance between the DLC (Data Link Connector) C251-6, circuit VDB04 (WH/BU), harness side and the DLC (Data Link Connector) C251-14, circuit VDB05 (WH), harness side.
Is the resistance between 54 and 66 ohms?
Yes
GO to A6.
No
For 3.5L engine, GO to A4.
For 3.5L GTDI engine, GO to A5.
A4 CHECK THE HS-CAN (High Speed Controller Area Network) CIRCUITS BETWEEN THE PCM AND THE DLC (Data Link Connector) FOR AN OPEN - 3.5L
- Disconnect: PCM C175B.
- Measure the resistance between the PCM C175B-2, circuit VDB04 (WH/BU), harness side and the DLC (Data Link Connector) C251-6, circuit VDB04 (WH/BU), harness side.
- Measure the resistance between the PCM C175B-3, circuit VDB05 (WH), harness side and the DLC (Data Link Connector) C251-14, circuit VDB05 (WH), harness side.
Are the resistances less than 5 ohms?
Yes
CONNECT the negative battery cable. GO to A6.
No
REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
A5 CHECK THE HS-CAN (High Speed Controller Area Network) CIRCUITS BETWEEN THE PCM AND THE DLC (Data Link Connector) FOR AN OPEN - 3.5L GTDI
- Disconnect: PCM C1381B.
- Measure the resistance between the PCM C1381B-59, circuit VDB04 (WH/BU), harness side and the DLC (Data Link Connector) C251-6, circuit VDB04 (WH/BU), harness side.
- Measure the resistance between the PCM C1381B-58, circuit VDB05 (WH), harness side and the DLC (Data Link Connector) C251-14, circuit VDB05 (WH), harness side.
Are the resistances less than 5 ohms?
Yes
CONNECT the negative battery cable. GO to A6.
No
REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
A6 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the PCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new PCM. CLEAR the DTCs. REPEAT the network test with the scan tool.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.