Pinpoint Test E: DTC U0164

Smart Junction Box (SJB)

Pinpoint Tests

Pinpoint Test E: DTC U0164

Normal Operation

The Smart Junction Box (SJB) and the HVAC module communicate using the Medium Speed Controller Area Network (MS-CAN). Messages are exchanged between the modules on the MS-CAN for the purposes of determining what functions are being carried out.

- DTC U0164 (Lost Communication With HVAC Control Module (EATC)) - set by the SJB whenever it loses communication with the HVAC module if the ignition is in the ON position for a minimum of 5 seconds (not in the START position) and the SJB supply voltage is greater than 10.5 volts.

This pinpoint test is intended to diagnose the following:

- Module communication
- HVAC module
- SJB



PINPOINT TEST E: DTC U0164

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E1 VERIFY CUSTOMER CONCERN


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

Yes
GO to E2.

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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E2 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 E3.

No
REFER to Information Bus, The HVAC Module Does Not Respond To The Scan Tool.

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E3 RETRIEVE THE RECORDED DTCs FROM THE SELF-TEST


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

Yes
For DTC B1317, GO to Pinpoint Test B. Pinpoint Test B: DTC B1317

For DTC B1318, GO to Pinpoint Test C. Pinpoint Test C: DTC B1318

No
GO to E4.

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E4 RECHECK THE SJB DTCs


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

- Clear the DTCs. Repeat the SJB self-test.
- Is DTC U0164 still present?

Yes
INSTALL a new HVAC module. TEST the system for normal operation. REPEAT the SJB self-test.

If DTC U0164 is still present, INSTALL a new SJB. REFER to Smart Junction Box (SJB) Smart Junction Box (SJB).

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

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