I just went to leave my house and my 850 turbo wagon would not start. I pulled the codes and got
A1: 124 - Mode selector faulty or short-circuit to ground.
A2: 335 - Request for malfunction indicator lamp (MIL) from AW 50-42 TCM, signal faulty.

My car has 200,000 miles and I do not believe the PNP has ever been replaced and am wondering if that is the cause. I just read through some posts to find the answer and don't feel certain it is the PNP. However, I did read a post that mentioned having a starting issue after switching from Sport back to Economy on the tranny control - which I just happen to do today for some unknown reason. Is there a corelation here?? As a side note/issue, I just replaced my rear ABS sensors last weekend (yes, I disconnected the battery) and I'm still pulling 142, 213, and 214 on A3 (yes, I reset them and my ABS light does not come on, but the "light bulb" ligt comes on when I hit the brakes). Is there a correlation between the ABS and the tranny or car not starting.

Any help would be great.

Wes

 

Does it turn over at all? (I mean crank but not start or not crank at all)

 

It cranks over just like it should. It is not acting as if it is in gear.

 

Do you think it is just my mode selector and nothing else. I've never pulled a 313 so I wouldn't think it would be the PNP.

 

If the PNP was bad the starter wouldn't crank over or the car will run but the arrow will flash.

If it cranks over then you will need to start with the basics.
Fuel
spark
injection pluse

 

The A1: 124 code (Mode selector faulty or short-circuit to ground) is in reference to the Ride mode selector next to the gear shifter, correct?

 

Yes that code trips as well as teh PNP usually clear the code and see if it comes right back.

 

Yes, after clearing they both come right back. I just went to http://www.volvoclub.org.uk/tech/ser...sDiagnosis.pdfand I'm going to test in Mode 2 and see where the fault is.

 

Okay, so everything checked out fine in Mode 2 and now I'm not pulling any codes in A1, but I'm still pulling the 335 on A2. I have no idea how to check a fault between the TCM and ECM. Apparently the fault (short or intermittent short to ground)is in the wiring between ECM terminal B26 and TCM terminal B15. Help, anyone??? I really don't want to tow my car in to the dealer.

 

It is a pain to ding into the wiring.

Have you pulled and computers and cleaned the connections yet?

 

Okay, First I checked the mode selector in Mode 2 and it was bad, so I replaced it. Car still won't start. Now, I'm thinking something else just happen to go out at the same time. So, I checked the ignition, coil, fuel pump, etc. - nothing! Everything is fine and I'm not pulling any codes. I am begining to believe my ECM or TCM is bad. What do you think? I've noticed some ECU's on ebay for $25 to $75. I'm fine spending the money on both just to see if it will work. Could I put a T5 ECM in my regular 850 turbo?

 

It should work.
I have a chippped computer that I swap between my 1995R and the wifes 1996 Turbo car.
Also I know for sure you can swap a turbo and a R computer.

 

Nice!! Thanks, I guess I'll give it a try. Have you heard of cars not starting because of a bad ECM?

 

Very rarely. I don't see if often at all.

 

Have you inspected/tested the following?:

- Fuel pump or pump relay.
- MAF(Mass Air Flow) sensor.
- CPS (Camshaft Position Sensor).
- Neglect.
- Etc...

Refer tomy 2nd post in the followingthread to see if anything has been neglected:

https://volvoforums.com/m_48928/tm.htm


JPN