Pinpoint Test A: DTC U0100:87

Body Control Module (BCM)

Pinpoint Tests

Pinpoint Test A: DTC U0100:87

Normal Operation

- DTC U0100:87 (Lost Communication With ECM/PCM "A": Missing Message) - sets in the BCM if data messages received (vehicle speed) from the PCM are missing for greater than 5 minutes. For a complete list of all network messages, refer to Module Communications Network Testing and Inspection.

This pinpoint test is intended to diagnose the following:

- Communication network concern
- PCM
- BCM

PINPOINT TEST A: DTC U0100:87

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A1 VERIFY THE SCAN TOOL CAN COMMUNICATE WITH THE PCM

- Connect the scan tool.
- Check that a vehicle session can be established using the scan tool.
- Can a vehicle session be established?

Yes
GO to A2.

No
REFER to Module Communications Network Testing and Inspection, The PCM Does Not Respond To The Scan Tool.

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A2 CHECK THE BCM CONTINUOUS MEMORY DTCs

- Ignition ON.
- Enter the following diagnostic mode on the scan tool: BCM Self-Test.
- Clear the DTCs. Repeat the BCM self-test.
- Is DTC U0100:87 retrieved again?

Yes
GO to A3.

No
The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

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A3 RETRIEVE THE RECORDED DTCs FROM THE BCM SELF-TEST

- Check for recorded BCM DTCs from the self-test.
- Is DTC U3003:16 or DTC U3003:17 recorded?

Yes
For DTC U3003:16, GO to Pinpoint Test F. For DTC U3003:17, GO to Pinpoint Test G. Pinpoint Test F: DTC U3003:16 Pinpoint Test G: DTC U3003:17

No
GO to A4.

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A4 CHECK FOR DTC U0100 SET IN OTHER MODULES

- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self-Test.
- Retrieve the continuous memory DTCs from all modules.
- Is DTC U0100 or DTC U0100:87 set in other modules?

Yes
INSTALL a new PCM. REFER to Electronic Engine Controls Powertrain Control Module (PCM). TEST the system for normal operation.

No
INSTALL a new BCM. REFER to Body Control Module (BCM) Service and Repair. TEST the system for normal operation

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