Pinpoint Tests BK: DTC U0166

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test BK: DTC U0166

Normal Operation
- DTC U0166 (Lost Communication With Auxiliary Heater Control Module) - sets in continuous memory if data messages received from the Auxiliary Heater Control Module (AHCM) over the Medium Speed Controller Area Network (MS-CAN) are missing for greater than 5 seconds.

This pinpoint test is intended to diagnose the following:

- AHCM
- Instrument Cluster (IC)



PINPOINT TEST BK: DTC U0166

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BK1 VERIFY THE CUSTOMER CONCERN


- Ignition ON.
- Verify that there is an observable symptom present.
- Is an observable symptom present?

Yes
GO to BK2.

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

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BK2 CHECK THE COMMUNICATION NETWORK


- Enter the following diagnostic mode on the scan tool: Network Test .
- Carry out the network test.
- Does the ACM pass the network test?

Yes
GO to BK3.

No
REFER to Information Bus.

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BK3 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST


- Check for recorded IC DTCs from the self-test.
- Is DTC B1317 or DTC B1318 recorded?

Yes
GO to Pinpoint Test BA (B1317) or GO to Pinpoint Test BB (B1318). Pinpoint Tests BA: DTC B1317 Pinpoint Tests BB: DTC B1318

No
GO to BK4.

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BK4 RECHECK THE IC DTCs


NOTE: If new modules were installed prior to the DTC being set, the module configuration may be incorrectly set during the Programmable Module Installation (PMI) or the PMI may not have been carried out.

- Clear the DTCs. Repeat the IC self-test.
- Is DTC U0166 still present?

Yes
INSTALL a new AHCM. CLEAR the DTCs. REPEAT the IC self-test.

If DTC U0166 is still present, INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.

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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