Pinpoint Test A: The PCM Does Not Respond To The Scan Tool
Communications Network
Pinpoint Tests
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, 4.6L 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. Refer to Battery, Mounting and Cables Battery Disconnect.
NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test. Inspection and Verification
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A1 CHECK THE DLC PINS FOR DAMAGE
- Ignition OFF.
- Disconnect the scan tool cable from the Data Link Connector (DLC).
- Inspect the DLC pins 6 and 14 for damage.
- Are DLC pins 6 and 14 OK?
Yes
GO to A2.
No
REPAIR the DLC as necessary. CLEAR the DTCs. REPEAT the network test with the scan tool.
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A2 VERIFY WHETHER OTHER HS-CAN 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 modules passed the network test.
- Is the text "pass" or a DTC listed next to the ABS module, Instrument Cluster (IC), PCM or Vehicle Dynamics Module (VDM)?
Yes
If "pass" or a DTC was listed next to the PCM, a network fault is not currently present. GO to Pinpoint Test J to diagnose an intermittent HS-CAN fault condition. Pinpoint Test J: Intermittent No High Speed Controller Area Network (HS-CAN) Communication, One Or More Modules Are Not Respond
If "pass" or a DTC was listed next to one or more modules other than the PCM, GO to A3.
No
No modules are currently communicating on the HS-CAN. GO to Pinpoint Test K to diagnose no HS-CAN communication. Pinpoint Test K: No High Speed Controller Area Network (HS-CAN) Communication, All Modules Are Not Responding
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A3 VERIFY THE COMPUTERS AND CONTROL SYSTEMS INFORMATION PINPOINT TEST QA HAS BEEN CARRIED OUT
- Verify that pinpoint test QA has been carried out.
- Has pinpoint test QA been carried out?
Yes
GO to A4.
No
REFER to Computers and Control Systems, pinpoint test QA to diagnose no communication with the PCM.
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A4 CHECK THE PCM GROUND CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the PCM, harness side and ground as follows:
- Are the resistances less than 5 ohms?
Yes
CONNECT the PCM. GO to A5.
No
REPAIR the circuit in question. CONNECT the PCM. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
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A5 CHECK THE HS-CAN TERMINATION RESISTANCE
- Measure the resistance between the DLC C251-6, circuit 1827 (WH/LG), harness side and the DLC C251-14, circuit 1828 (PK/LG), harness side.
- Is the resistance between 54 and 66 ohms?
Yes
CONNECT the negative battery cable. GO to A7.
No
GO to A6.
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A6 CHECK THE HS-CAN CIRCUITS BETWEEN THE PCM AND THE DLC FOR AN OPEN
- Measure the resistance between the PCM C175b-11, circuit 1827 (WH/LG), harness side and the DLC C251-6, circuit 1827 (WH/LG), harness side.
- Measure the resistance between the PCM C175b-23, circuit 1828 (PK/LG), harness side and the DLC C251-14, circuit 1828 (PK/LG), harness side.
- Are the resistances less than 5 ohms?
Yes
CONNECT the negative battery cable. GO to A7.
No
REPAIR the circuit in question. CONNECT the PCM. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
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A7 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. REFER to Electronic Engine Controls Service and Repair. 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.
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