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DTC U0166 [MZR-CD (RF Turbo)]

BME010290000205

DTC U0166 | Lost communication with AUXILIARY HEATER CONTROL MODULE
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DETECTION CONDITION | • PCM cannot receive any signals from auxiliary heater control module (water heater unit). Diagnostic support note • MIL comes on. • FREEZE FRAME DATA is available. • DTC is stored in the PCM memory.
POSSIBLE CAUSE | • Short to ground circuit between water heater unit terminal 1I and PCM terminal 13 • Short to ground circuit between water heater unit terminal 1K and PCM terminal 39 • Open circuit between water heater unit terminal 1I and PCM terminal 13 • Open circuit between water heater unit terminal 1K and PCM terminal 39
• Short to power circuit between water heater unit terminal 1I and PCM terminal 13
• Short to power circuit between water heater unit terminal 1K and PCM terminal 39
• Damaged water heater unit
• Damaged PCM

Diagnostic procedure

STEP | INSPECTION | ACTION
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1 | VERIFY FREEZE FRAME DATA HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded? | Yes | Go to the next step.
No | Record FREEZE FRAME DATA on repair order, then go to the next step.
2 | VERIFY RELATED SERVICE INFORMATION AVAILABILITY • Check for related Service Information availability. • Is any related Service Information available? | Yes | Perform repair or diagnosis according to available Service Information. • If vehicle is not repaired, go to the next step.
No | Go to the next step.
3 | VERIFY RELATED PENDING CODE OR STORED DTCS • Turn the engine switch off, then to the ON position (Engine off). • Verify related pending code or stored DTCs. • Is DTC U0073 for present? | Yes | Go to the applicable DTC inspection. (See DTC U0073 [MZR-CD (RF Turbo)].)
No | Go to the next step.
4 | INSPECT TCM CONNECTOR FOR POOR CONNECTION • Turn the engine switch off. • Disconnect the water heater unit connector. • Inspect for poor connection (such as damaged/pulled-out pins, corrosion). • Is there any malfunction? | Yes | Repair the terminal, then go to Step 9.
No | Go to the next step.
5 | CHECK CAN COMMUNICATION LINE FOR SHORT TO GROUND • Inspect for continuity between the following terminals and body ground:

  - Water heater unit connector terminal 1I (wiring harness-side)
  - Water heater unit connector terminal 1K (wiring harness-side)

• Is there continuity?
Yes
Repair or replace the wiring harness, then go to Step 9.
No | Go to the next step.
6 | CHECK CAN COMMUNICATION LINE FOR SHORT TO POWER • Measure the voltage between following terminals and body ground:

  - Water heater unit connector terminal 1I (wiring harness-side)
  - Water heater unit connector terminal 1K (wiring harness-side)

• Is the voltage B+?
Yes
Repair or replace the wiring harness, then go to Step 9.
No | Go to the next step.
7 | INSPECT PCM CONNECTOR FOR POOR CONNECTION • Turn the engine switch off. • Disconnect the PCM connector. • Inspect for poor connection (such as damaged/pulled-out pins, corrosion). • Is there any malfunction? | Yes | Repair the terminal, then go to Step 9.
No | Go to the next step.
8 | CHECK CAN COMMUNICATION LINE FOR OPEN CIRCUIT • Disconnect the PCM connector. • Inspect for continuity between the following terminals:

  - Water heater unit connector terminal 1I (wiring harness-side) and PCM connector terminal 13 (wiring harness-side)
  - Water heater unit connector terminal 1K (wiring harness-side) and PCM connector terminal 39 (wiring harness-side)

• Is there continuity?
Yes
Repair or replace the wiring harness, then go to Step 9.
No | Go to the next step.
9 | VERIFY TROUBLESHOOTING OF DTC U0166 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the WDS or equivalent. • Start the engine and warm it up completely. • Is the PENDING CODE of same DTC present? | Yes | Replace the PCM, then go to the next step.
No | Go to the next step.
10 | VERIFY AFTER REPAIR PROCEDURE • Perform "After Repair Procedure". (See AFTER REPAIR PROCEDURE [MZR-CD (RF Turbo)].) • Is there any DTC present? | Yes | Go to the applicable DTC inspection. (See DTC TABLE [MZR-CD (RF Turbo)].)
No | Troubleshooting completed.