Pinpoint Tests AT: DTC U0164

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test AT: DTC U0164

Normal Operation
- DTC U0164 (Lost Communication With HVAC Control Module (EATC)) - sets in continuous memory if data messages received from the HVAC module 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:

- HVAC module
- Instrument Cluster (IC)



PINPOINT TEST AT: DTC U0164

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AT1 VERIFY THE CUSTOMER CONCERN


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

Yes
GO to AT2.

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

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AT2 CHECK THE COMMUNICATION NETWORK


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

Yes
GO to AT3.

No
REFER to Information Bus.

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AT3 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST


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

Yes
Go To Pinpoint Test AK (B1317) or Go To Pinpoint Test AL (B1318). Pinpoint Tests AK: DTC B1317 Pinpoint Tests AL: DTC B1318

No
GO to AT4.

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AT4 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 U0164 still present?

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

If DTC U0164 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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