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2008 - MX-5 - Suspension

DTC U0127



DTC U0127

  • Communication failure between instrument cluster and keyless receiver

DETECTION CONDITION

  • The instrument cannot receive signal from the keyless CM or keyless receiver.

POSSIBLE CAUSE

    With advanced keyless system and keyless entry system
  • Open or short circuit in the wiring harness between the keyless CM terminal 3R and the instrument cluster terminal 2V.

  • Keyless control module malfunction.

  • Instrument cluster malfunction.

  • Poor connection at connectors (female terminal)

    Without advanced keyless system and keyless entry system
  • Open or short circuit in the wiring harness between the keyless receiver terminal D and the instrument cluster terminal 2V.

  • Keyless receiver malfunction.

  • Instrument cluster malfunction.

  • Poor connection at connectors (female terminal)


With Advanced Keyless System or Keyless Entry System

Diagnostic procedure

STEP

INSPECTION

ACTION

1

INSPECT WHEEL UNIT SIGNAL FOR OPEN CIRCUIT
  • Turn the ignition switch off.

  • Disconnect keyless CM and instrument cluster connectors.

  • Inspect for continuity between keyless CM terminal 3R (harness-side) and instrument cluster terminal 2V (harness-side).

  • Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness for an open circuit between keyless CM terminal 3R and instrument cluster terminal 2V, then go to Step 5.

2

INSPECT WHEEL UNIT SIGNAL FOR SHORT TO POWER
  • Turn the ignition switch off.

  • Disconnect keyless CM and instrument cluster connectors.

  • Measure the voltage between keyless CM terminal 3R (harness-side) and ground.

  • Is there B+?

Yes

Repair or replace the wiring harness for a short to power between keyless CM terminal 3R and instrument cluster terminal 2V, then go to Step 5.

No

Go to the next step.

3

INSPECT WHEEL UNIT SIGNAL FOR SHORT TO GROUND
  • Turn the ignition switch off.

  • Disconnect keyless CM and instrument cluster connectors.

  • Inspect for continuity between keyless CM terminal 3R (harness-side) and ground.

  • Is there continuity?

Yes

Repair or replace the wiring harness for a short to ground between keyless CM terminal 3R and instrument cluster terminal 2V, then go to the next step.

No

With advanced keyless system: go to the next step.

With keyless entry system: go to Step 5.

4

INSPECT FOR KEYLESS CM MALFUNCTION
  • Turn the ignition switch off.

  • Using the M-MDS, perform the DTC inspection for the keyless CM.

  • Is any DTCs present?

Yes

Go to the applicable DTC inspection. (See DTC TABLE [ADVANCED KEYLESS SYSTEM].)

No

Go to the next step.

5

VERIFY TROUBLESHOOTING COMPLETED

Yes

No

Go to the next step.

6

VERIFY AFTER REPAIR PROCEDURE
  • Drive the vehicle at a speed of 25 km/h {15.5 mph} or more for 10 min or more.

  • Are there any other DTCs present?

Yes

Go to the applicable DTC inspection. (See TIRE PRESSURE MONITORING SYSTEM (TPMS) ON-BOARD DIAGNOSIS.)

No

DTC troubleshooting completed.


Without Advanced Keyless System and Keyless Entry System

Diagnostic procedure

STEP

INSPECTION

ACTION

1

INSPECT WHEEL UNIT SIGNAL FOR OPEN CIRCUIT
  • Turn the ignition switch off.

  • Disconnect keyless receiver and instrument cluster connectors.

  • Inspect for continuity between keyless receiver terminal D (harness-side) and instrument cluster terminal 2V (harness-side).

  • Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness for open circuit between keyless receiver terminal D and instrument cluster terminal 2V, then go to Step 4.

2

INSPECT WHEEL UNIT SIGNAL FOR SHORT TO POWER
  • Turn the ignition switch off.

  • Disconnect keyless receiver and instrument cluster connectors.

  • Measure the voltage between keyless receiver terminal D (harness-side) and ground.

  • Is there B+?

Yes

Repair or replace the wiring harness for a short to power between keyless receiver terminal D and instrument cluster terminal 2V, then go to Step 4.

No

Go to the next step.

3

INSPECT WHEEL UNIT SIGNAL FOR SHORT TO GROUND
  • Turn the ignition switch off.

  • Disconnect keyless receiver and instrument cluster connectors.

  • Inspect for continuity between keyless receiver terminal D (harness-side) and ground.

  • Is there continuity?

Yes

Repair or replace the wiring harness for a short to ground between keyless receiver terminal D and instrument cluster terminal 2V, then go to the next step.

No

Replace keyless receiver, then go to the next step.

(See KEYLESS RECEIVER REMOVAL/INSTALLATION[ADVANCED KEYLESS SYSTEM].)

4

VERIFY TROUBLESHOOTING COMPLETED

Yes

No

Go to the next step.

5

VERIFY AFTER REPAIR PROCEDURE
  • Drive the vehicle at a speed of 25 km/h {15.5 mph} or more for 10 min or more.

  • Are there any other DTCs present?

Yes

Go to the applicable DTC inspection. (See TIRE PRESSURE MONITORING SYSTEM (TPMS) ON-BOARD DIAGNOSIS.)

No

DTC troubleshooting completed.




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