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
Normal Operation
The PCM communicates with the scan tool through the High Speed Controller Area Network (HS-CAN). An Integrated Diagnostic System (IDS) session cannot be established if PCM communication fails when attempting to identify the vehicle.
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 will result in false resistance readings.
A1 VERIFY WHETHER OTHER HS-CAN (High Speed Controller Area Network) MODULES PASSED THE NETWORK TEST
- Enter the following diagnostic mode on the scan tool: Network Test.
- In the LH pane of the IDS (Integrated Diagnostic System) 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): ABS module, Instrument Panel Cluster (IPC), Restraints Control Module (RCM), PCM, Trailer Brake Control (TBC) module?
Yes
If "pass" or a DTC was listed next to the PCM, a network fault is not currently present. GO to Pinpoint Test L Pinpoint Test L: No Medium Speed Controller Area Network (MS-CAN) Communication, All Modules Are Not Responding to diagnose an intermittent HS-CAN (High Speed Controller Area Network) fault condition.
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 K Pinpoint Test K: The Accessory Protocol Interface Module (APIM) Does Not Respond To The Scan Tool to diagnose no HS-CAN (High Speed Controller Area Network) communication.
A2 VERIFY COMPUTERS AND CONTROL SYSTEMS INFORMATION PINPOINT TEST QA HAS BEEN CARRIED OUT
- Verify that Computers and Control Systems Information pinpoint test QA has been carried out.
Has Computers and Control Systems Information pinpoint test been carried out?
Yes
GO to A3.
No
REFER to Computers and Control Systems Information, Pinpoint Tests, pinpoint tests 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.
- Measure the resistance between the Data Link Connector (DLC) 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
CONNECT the negative battery cable. GO to A5.
No
GO to A4.
A4 CHECK THE HS-CAN (High Speed Controller Area Network) CIRCUITS BETWEEN THE PCM AND THE DLC (Data Link Connector) FOR AN OPEN
- Disconnect: PCM C175B.
- Measure the resistance between the PCM, harness side, and the DLC (Data Link Connector), harness side, as follows:
Engine PCM Connector-Pin DLC (Data Link Connector) Connector-Pin Circuit 4.6L and 5.4L C175B-59 C251-6 VDB04 (WH/BU) 6.8L C1551B-11 C251-6 VDB04 (WH/BU) 4.6L and 5.4L C175B-43 C251-14 VDB05 (WH) 6.8L C1551B-23 C251-14 VDB05 (WH)
Are the resistances less than 5 ohms?
Yes
CONNECT the negative battery cable. GO to A5.
No
REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
A5 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. CLEAR the DTCs. REPEAT the network test with the scan tool.