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2008 - MX-5 - Body and Accessories

NO.4 ADVANCED KEYLESS START FUNCTION INOPERATIVE [ADVANCED KEYLESS SYSTEM]



4

Advanced keyless start function inoperative

POSSIBLE CAUSE

  • Malfunction in the transmitter (card key).

  • Malfunction in the keyless control module.

  • Malfunction in the keyless receiver.

  • Malfunction in the keyless antenna.

  • Malfunction in the PCM.


Diagnostic procedure

STEP

INSPECTION

ACTION

1

  • Retrieve the advanced keyless system DTC using the M-MDS.

  • Are there DTC displayed?

Yes

Perform the applicable DTC diagnostic procedures.

No

Go to the next step.

2

  • Attempt to start the engine using the key.

  • Does engine start?

Yes

Go to the next step.

No

Go to symptom troubleshooting flow No.3 in 01-03 section.

3

  • Does the keyless indicator light (green) turn ON when pressing the start knob?

Yes

Go to step 11.

No

    If the keyless indicator light (green) does not illuminate:
  • Go to the next step.

    If the keyless warning light (red) is flushing:
  • Go to Step 6.

    If the keyless warning light (red) illuminates:
  • Go to Step 9.

4

  • Bring the transmitter (card key) inside the passenger compartment.

  • Measure the voltage at the keyless control module terminal 3N (push switch) while pushing the start knob.

  • Is the voltage B+?

Yes

Go to the next step.

No

  • Inspect the wiring harness between the steering lock unit and keyless control.

    • If the harness is normal, replace the steering lock unit.

    • If the harness is malfunctioning, repair the wiring harness.

  • Go to the next step.

5

  • Replace with a transmitter (card key) battery known to be good.

  • Bring the transmitter (card key) inside the passenger compartment.

  • Does the keyless entry system operate properly?

Yes

Replace the transmitter (card key). Then go to the next step.

No

Go to the next step.

6

  • Simulate the following keyless antenna using the M-MDS:.

    • ANT_RF# (exterior, RF keyless antenna: terminals 2A and 2B)

    • ANT_LF# (exterior, LF keyless antenna: terminals 2C and 2D)

    • ANT_BK# (exterior, rear keyless antenna: terminals 2E and 2F)

    • ANT_INN1# (interior, trunk keyless antenna: terminals 2G and 2H)

    • ANT_INN2# (interior, rear keyless antenna: terminals 2I and 2J)

    • ANT_INN3# (interior, middle keyless antenna: terminals 2K and 2L)

    • ANT_INN4# (interior, front keyless antenna: terminals 3G and 3H)

  • Does each antenna operate properly (ON/OFF)?

Yes

Go to the next step.

No

  • Inspect for open or short circuit between suspect keyless antenna and keyless control module.

    • If the wiring harness normal, replace suspect keyless antenna, then go to the next step.

    • If the wiring harness is not normal, repair or replace for open or short circuit, then go to the next step.

7

  • Measure the pulse profile using an oscilloscope at the keyless control module terminal 3U while operating the transmitter (card key).

  • Is the pulse profile become long at moment of transmitter operation?

Yes

Go to the next step.

No

  • Inspect the wiring harness between the keyless receiver and the keyless control module.

    • If the harness is normal, replace the keyless receiver.

    • If the harness is malfunctioning, repair the wiring harness.

  • Go to the next step.

8

Yes

Go to the next step.

No

Repair or replace malfunctioning part according to inspection result.

9

  • Measure the keyless control module terminal 3P voltage.

  • Is the voltage approx. 5.0 V?

Yes

Go to the next step.

No

Inspect for open or short circuit between keyless control module terminal 3P (75-pin) and keyless receiver unit terminal C (6-pin).

Is the wiring harness is not normal, repair or replace for open or short circuit, then go to the next step.

If the wiring harness is normal, go to the next step.

10

  • Replace steering lock unit.

  • Turn the start knob to START position.

  • Does the advanced keyless start operate properly?

Yes

Troubleshooting completed.

Explain repairs to the customers.

No

Replace the keyless control module.

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

Then go to the next step.

11

  • Does the keyless entry system operate properly?

Yes

Troubleshooting completed. Explain repairs to the customers.

No

Re-inspect the malfunction symptoms, then repeat form step 1 if malfunction recurs.




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