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I am feeling stuck and frustrated with my 2001 996TT. Here is some information that may help someone guide me in the right direction:
Previous to my current issue - I had the well known "Oil Indicator Failure" issue and had my cluster worked on by ModuleMasters. After the fix, I had no more issues. During the winter I powdercoated and rebuilt my calipers. Due to COVD19 I was only able to retrieve the calipers somewhat recently from the powdercoater. I have driven the car maybe 5 times since the cluster was repaired and calipers were rebuilt.
Yesterday (the day the car did not start) I drove the car a few miles to the gym, took a neighbor out for a cruise and ran a couple errands. So I shut the car off and started it back up about 5 or 6 times with no issues what so ever. The car ran perfect! I parked the car in my driveway when I got home and went outside to start it 1 hour later. Turned the key annnd nothing. I then noticed that the cluster showed an engine error, airbag error and low fuel (I believe I had around 1/4 tank still).
I began to Troubleshoot:
-Checked Battery Voltage - 12.5V
-Plugged in my Ethos Edge Scanner - No Communication even with generic OBD2
-Checked Fuses - All Good
-Checked Starter Relay - Tested Good but does not activate with the ignition.
-Inspected the BCM and BCM Fuse - Everything looks good and fuse was good.
-Purchased a new Ignition Switch today - Replaced it and nothing has changed.
I am curious if I am missing something here? What would your next step be? I cannot find a troubleshooting guide for diagnosing the Cluster-->BCM-->ECM Communication.
Any help is greatly appreciated! I live in Danbury, CT if anyone is close by.
Hi Gordon. You may have better responses over in the Turbo forum: https://rennlist.com/forums/turbo-te...sion-areas-50/
The 6TT uses a different ECU/DME and wiring from the NA cars. But the immobilizer is similar.
To have the start interlock relay fire, the DME needs (1) immobilizer code from the key head; (2) message over CAN from the instrument cluster with matching VIN's; (3) clutch switch made by pushing clutch in.
If a start is denied by the immobilizer there's a code stored in the DME. At least that's my recollection.
Given your experience I'd suspect the clutch switch. It can easily be bypassed and it's better for the engine to start it in neutral with the clutch released anyway.
However as you can't even communicate with the DME with your OBD2 reader there may actually be something wrong with the DME or the wiring, or perhaps your OBD2 reader.
If you try your OBD2 reader on another car and it's working I might check the fuses: C1 and C2. Also the OBD2 plug has it's own fuses: B1 and B10.
The DME/ECU and ignition relays are on the rear relay bracket, behind the back seat, under the Bose subwoofer and the carpet, and fairly hard to get to.
Gordon,
You can do as Aaron suggests and interrogate the cars security system, but that sounds a little premature. You will probably get some sage advice from the turbo forum too, as I'm no guru on P cars, but you may be better off to just check the part that isn't working. Check for voltage at back of starter and go from there.
Hi Gordon. You may have better responses over in the Turbo forum: https://rennlist.com/forums/turbo-te...sion-areas-50/
The 6TT uses a different ECU/DME and wiring from the NA cars. But the immobilizer is similar.
To have the start interlock relay fire, the DME needs (1) immobilizer code from the key head; (2) message over CAN from the instrument cluster with matching VIN's; (3) clutch switch made by pushing clutch in.
If a start is denied by the immobilizer there's a code stored in the DME. At least that's my recollection.
Given your experience I'd suspect the clutch switch. It can easily be bypassed and it's better for the engine to start it in neutral with the clutch released anyway.
However as you can't even communicate with the DME with your OBD2 reader there may actually be something wrong with the DME or the wiring, or perhaps your OBD2 reader.
If you try your OBD2 reader on another car and it's working I might check the fuses: C1 and C2. Also the OBD2 plug has it's own fuses: B1 and B10.
The DME/ECU and ignition relays are on the rear relay bracket, behind the back seat, under the Bose subwoofer and the carpet, and fairly hard to get to.
Thanks for the reply!
I forgot to mention that I jumped the clutch switch, but that did not help. I verified that the scanner works on my other cars, I checked all fuses and Relays (DME, Fuel Pump, Starter) So I have the back opened up and DME/Relays are visible.
I jumped the starter relay and the car turned over when I cycled the key in the ignition. I checked for shorts and also locked the drivers side door with the key while pressing the lock button on the FOB and the Immobilizer light flashed quickly and shuts off once I unlock the car like it should.
I am also suspecting an issue with the Immobilizer or DME. "Specialized ECU Repair" charges $95 to look at the DME, Immobilizer and Key. I also only have one key for the car, so I thought this would be a good time to get another one, which they also do. I am going to check the ground in the right rear of the car (heard this can cause issues). I will post on the Turbo Forums to see if anyone has any other suggestions - thank you for letting me know!
Gordon,
You can do as Aaron suggests and interrogate the cars security system, but that sounds a little premature. You will probably get some sage advice from the turbo forum too, as I'm no guru on P cars, but you may be better off to just check the part that isn't working. Check for voltage at back of starter and go from there.
Thanks for your input. I jumped the starter relay and the car turns over with the key. I am suspecting an issue with the DME or Immobilizer. I will post over in the turbo forum and see if I get any more input. I appreciate your response!
Your car is different than ours, but maybe similar in some respects. From the battery the positive lead connects to a power distribution box, that contains 80 amp fusible links. If any system of the car is not getting 12V, it's a good place to start.
Thanks for your input. I jumped the starter relay and the car turns over with the key. I am suspecting an issue with the DME or Immobilizer. I will post over in the turbo forum and see if I get any more input. I appreciate your response!
Okay that forum would be a great resource.
I don't quite understand your sentence "I jumped the starter relay and the engine turns over with the key. Not real sure, but a better test would be to put a coil between pin 85 and 86 on relay panel that holds stop lock relay and see if when turning key a 12volt bulb illuminates. Or a multi meter reading. If not I think,but not sure that that holding coil gets its juice from MAF sensor.
Okay that forum would be a great resource.
I don't quite understand your sentence "I jumped the starter relay and the engine turns over with the key. Not real sure, but a better test would be to put a coil between pin 85 and 86 on relay panel that holds stop lock relay and see if when turning key a 12volt bulb illuminates. Or a multi meter reading. If not I think,but not sure that that holding coil gets its juice from MAF sensor.
I put a jumper wire between 30 and 87 and cranked the car successfully. It seems like a DME issue or possibly immobilizer. I’ll have to start ohm-ing out wires to see if any are the culprit. Printing out wiring diagrams and will try again tomorrow..
Okay you manually did what the start relay does.
If you can take a reading at pin 85(ground) and pin 86 (12 volt side) that will indicate whether your wiring is faulty or the holding coil in the relay went bad.
07-16-2020, 05:49 PM
996TT No Start/No Crank - Please Help
