Pinpoint Test Q: DTC U0100:87

Anti-Theft - With Intelligent Access (IA)

Pinpoint Tests

Pinpoint Test Q: DTC U0100:87

Refer to Wiring Diagram Set 14, Module Communications Network for schematic and connector information. Diagrams By Number

Normal Operation
- DTC U0100:87 (Lost Communication With ECM/PCM "A": Missing Message) - a continuous memory DTC that sets only when the Remote Function Actuator (RFA) module does not receive the Passive Anti-Theft System (PATS) challenge or engine torque data messages from the PCM. It can also be caused by a low vehicle battery state of charge affecting the quality of communication between the modules.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Low battery state of charge
- RFA module
- PCM

PINPOINT TEST Q: DTC U0100:87

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Q1 CHECK THE BATTERY STATE OF CHARGE

- Check the battery state of charge with the battery condition test. Refer to Battery, Mounting and Cables Testing and Inspection.
- Does the battery pass the battery condition test?

Yes
GO to Q2.

No
REFER to Charging System Testing and Inspection to diagnose the low battery voltage condition.

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Q2 CHECK FOR MODULE COMMUNICATION ON THE HS-CAN

- Carry out the network test using the scan tool.
- Is the scan tool unable to communicate with any of the modules on the HS-CAN?

Yes
REFER to Module Communications Network Testing and Inspection to diagnose the module that is not communicating with the scan tool.

No
GO to Q3.

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Q3 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 self-test. If the concern is still present, GO to Q4.

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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Q4 CHECK FOR CORRECT RFA MODULE OPERATION

- Disconnect all the RFA module connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the RFA module 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 RFA module. REFER to Multifunction Electronic Modules Remote Function Actuator (RFA) Module. CLEAR the DTCs. REPEAT the self-test.

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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