1999 C70 quit running while driving down the road ( recloned ECU) Topic is solved

[abscate]

I'm still not sure we cleared fuel pump on this. Are you getting a solid 52 psi all the time with a good measurement of fuel pressure ?

Also, pull that 2/232 relay from the relay box under hood and check those terminals. Clean until they are shiny bright.

It's the first of four hidden under my ring finger, ouch, gotta get that ring resized...

Somebody at Volvo was sleeping when they labelled that fuse box, but Hades, my car has a 1998 vacuum diagram pm on the hood, so I should be thankful they at least got the parts right

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[volvooh]

Thanks.

I am getting 52/53 psi when the engine fails. I did this by hooking up the pressure tester and jumping the ignition relay, so the pump would keep running after the engine died. When it did I was at 52/35 lbs.

I installed the ECT, but same result.

I checked all the relays- all are clean and shiny. I pulled the 15 amp fuse for the fuel pump/coils. I did a voltage check while cranking and it registered a little over volt which I found a bit pecuilar, but on the '99 S70 the same test yeilded over 2 volts. Really not sure what that means, if any thing. The ignition switches from the two '99 are different, so not able to do a swap there. A quick once over on the switch- seems to be functioning normally.

I ordered an Icarsoft from Amazon that will be here on Monday. Its not the Vida Dice, but I have another one I use on our Range Rover and has worked well for me. It also has a 30 day warranty.

Beyond Crank, Cam, ECT, MAF sensors, fuel relay, and fuel pump (all check out) not sure what else to do. I am starting to think it may be an ECU issue.

[sleddriver]

.... I am going to change the Tstat and ECT for kicks- I noticed the fan came on right away from a cold start- I saw a thread where a bad ECT was displaying similar issues to mine. Probably can't do it tonight, maybe first thing tomorrow or tomorrow evening. I think I'll take you up on your MAF though, but I'll PM.

Any clue as to why when the car stalls the tach stays at its last position (say 2000 rpm) before falling back when you turn the key off?

Very odd the radiator fan would come on right away from a cold start...unless the A/C was ON.

I know 98's only have a single engine temp sensor and everything relies on it. So when it goes wobbly, all that relies on it does as well. What also goes wobbly is the harness connector. I had to replace the ECT due to an obvious fault, but also rebuild the connector itself as it was in very bad shape after 19yrs. Its symptoms were identical to a faulty ECT.

Your tach needle remaining at 2000 rpm is also weird....never heard of that. A 99 is quite different electrically from my 98, from what I understand and have been told by my indy.

Have you tried removing both battery cables, connecting a 1k or so power resistor between them, letting the whole electrical system discharge overnight, then reconnecting the next morning? Some might just short them together, but I wouldn't advise that as a large enough current flow might damage something. Better to allow it to slowly bleed down to nothing over time.

Can't remember if you had the whole engine/intake system smoke tested or not to find a vacuum leak.

[volvooh]

Thanks, tried the battery cable trick, but worth doing again.

Anyone know where the tacho gets its info from? Perhaps the sticking tacho when stalling is a clue to unraveling this.

[volvooh]

I got my icarsoft and immediately did a scan.

I got ECM- 912a as the code- a communication fault with the ECM/ETS? I read on other threads it points to a software issue with the ETS?

Any one have any insights?

[abscate]

Heres some detail from Alldata on ECM-912A

Is your cruise control functioning?


Condition
The control modules communicate with each other in a network via a standardized serial communication procedure - CAN (Controller Area Network) - for exchange of information. Diagnostic trouble code (DTC) ECM-912A is stored in the engine control module (ECM) if the throttle unit registers that communication with the engine control module (ECM) is disrupted or missing.

Condition
CAN communication is disabled
cruise control shut off
fuel shut-off system which follows accelerator pedal (AP) position
throttle closure when braking
the throttle follows accelerator pedal (AP) position
Possible source
contact resistance in terminals
open-circuit in one or both signal cables
one or both signal cables short-circuited to ground, voltage or each other
interference in wiring
defective engine control module (ECM)
Condition
ETS warning lamp lit
cruise control does not function at all
engine judders under acceleration
engine judders heavily after engine braking
uneven idle

[abscate]

More info - here is how you check if the fault is permanent or intermittant

ECM-912A COMMUNICATION CONTROL MODULE OR INTERNAL FAULT IN CONTROL MODULE
STATUS CHECK

Check to see is the fault is intermittent or permanent.
Start the engine.
Press the accelerator pedal (AP) down at the same time as the brake pedal is despressed.
The fault is intermittent if the engine speed (RPM) increases.

The fault is permanent if the engine speed (RPM) doe not increase.

[volvooh]

When I depress the gas and brake pedal, RPMs increase. Not sure about the cruise control...doesn't stay running long enough to use it!

I also cleared the ECM code and restarted the car. We'll see if it stalls.

Is my research correct, and what see you have written above- is this all pointing towards the ETS? Somebody at volvo really had their thinking cap on when they decided to put it under the intake! It'd been easier to deal with the computer.

BTW- I found a yellow label pull off on Ebay with the same P/N as mine 8644347- its $125 with a warranty. If its the ETS it might be worth a shot. It'd been easier to deal with the computer.

[abscate]

Lets let jimmy or mike chime in on the ETS - those guys are the gurus of ETS problems. I thought it was rare for them to cause a complete stall - I thought they went to limp mode in default.

We are getting close......

[volvooh]

I let the car run to its usual stall, occasionally monitoring with the scanner. Ran it in and out of gear. Pressed the gas and brake at the same time. Seemed to function and idle fine. When it finally stalled (took about 30 min) interestingly I lost communication with the ECM. I did get another fault in the combined instrutment system- CI 113- Fuel Sensor, Open Circuit. All other systems check out with no codes.

I'll post back once I can re-establish communication with the ECM. BTW- called my local volvo dealership. The ETS recall was done in 2006 with a new ETS installed. He said he just did another '99 last week. I'd like to see the bill for that one.