Transponder Key Invalid

B2385

Transponder Key Invalid

Fault symptoms
The car does not start. The message "KEY NOT ACCEPTED" appears on SID.

Condition
A key not programmed for this TWICE module is used or the transponder key is missing or is faulty.

Diagnostic help
"KEY NOT ACCEPTED" is shown on SID. Try using another key which is programmed for this TWICE module.

Main condition
The diagnostic trouble code is generated if a fault is found during two test cycles in succession. A test cycle lasts one second, i.e. it takes two seconds from when the fault occurs until a diagnostic trouble code is generated. If the fault disappears, the trouble code is deleted from the control module memory after the ignition has been turned on 20 times.

Diagnostic trouble codes are not generated if the voltage is below 11 V or over 14 V.

Check the wiring
Touch the wiring harness at several points and in different directions to reveal intermittent breaks and short-circuits in the wiring harness. Monitor the multimeter, test lamp or diagnostic instrument during the test.

Diagnostic procedure

1. Select diagnostic procedure.
- What are the car's fault symptoms?

THE ENGINE STARTS WITH ONE KEY BUT NOT WITH THE OTHER.
- Replace the top part of the key and program this as instructed in the Technical Description.
- Go to point 8.
THE ENGINE DOES NOT START WITH ANY KEY.
- Go to point 2.





2. Check the power supply
- Unplug the connector: antenna unit, immobilizer: (463)





- Turn the ignition switch to the ON position.





- Connect test lamp 86 11 857 between pin 1 of the female connector and a good grounding point.





- The test lamp should light.

Test results OK?
YES
- Go to point 3.
NO
- Repair or replace the wiring.
- Go to point 8.





3. Check the signal lead
- Unplug the connector: TWICE control module : (632)





- Measure the resistance
- Red test lead: antenna unit, immobilizer: 2





- Black test lead: TWICE control module: 39
- The reading should be 0 - 1 ohm

Test results OK?
YES
- Go to point 4.
NO
- Repair or replace the lead.
- Go to point 8.





4. Check the signal lead for a short-circuit to B+.
- Measure the voltage.
- Red test lead: antenna unit, immobilizer: 2





- Black test lead: TWICE control module: 39
- The value should be 0 - 1 V.

Test results OK?
YES
- Go to point 5.
NO
- Repair or replace the lead.
- Go to point 8.





5. Check the signal lead for a short-circuit to ground.
- Measure the resistance.
- Red test lead: antenna unit, immobilizer: 2





- Black test lead: TWICE control module: 39
- The value should be O.L.

Test results OK?
YES
- Go to point 6.
NO
- Repair or replace the lead.
- Go to point 8.





6. Check the ground lead.
- Measure the resistance.
- Red test lead: antenna unit, immobilizer: 3





- Black test lead: grounding point G24
2G- The reading should be 0 - 1 ohm

Test results OK?
YES
- Go to point 7.
NO
- Repair or replace the lead.
- Go to point 8.





7. Check the ground lead for a short-circuit to B+.
- Measure the voltage.
- Red test lead: antenna unit, immobilizer: 3





- Black test lead: grounding point G24
- The value should be 0 - 1 V.

Test results OK?
YES
- Replace: antenna unit, immobilizer
- Go to point 8.
NO
- Repair or replace the lead.
- Go to point 8.





8. Final check
- Clear the diagnostic trouble codes in all systems.





- Carry out a function check.
- Evaluate the function check.





- Check that the diagnostic trouble code has not recurred.

Has the diagnostic trouble code recurred?
YES
- See Before Changing A Control Module. Before Changing A Control Module
NO
- The steps taken to rectify the fault were correct.