From water pump to SRS

[azureblue]

Hokay now - I got a scan done with the official Volvo scanner, and there all sorts of "low voltage", etc., codes. The very reputable Volvo mechanic was puzzled, because he said the code errors don't make sense. That rear relay was checked, system voltage checked, the main relays on the CEM frame checked, relays checked for seating and contact corrosion. All connectors to the CEM were on thight. Voltage at the relays was not checked, though. The car did the same thing - if you don't start the car, just turn the key to position II, the turn signals, etc., don't wok at all, or are intermittent. But when the car is started, everything works great for a while, then the problem starts up again. Shutting down the car car and restarting usually corrects the problem for a while. We had an official Volvo manual / schematic, too. I can also read schematics, but we could not trace back to a common point. As I said previously, I thought it was caused by some thing may have bumped while changing the intake manifold to turbo pipe, but I checked that too, and the connectors to the alternator, which was replaced last December. And I checked the battery with my trickle charger, which said the battery was good. Voltage with engine running is right on target. I'm rechecking the schematic right now.


What stops working or is intermittent:
Turn signals
wipers, front and rear
sometimes headlights - this is new

Radio now works fine.
SRS warning stays on ( when the wipers, etc., quit working the SRS warning came on, also)

Maybe a pin came loose in a connector block or socket?
I was told it was the CEM, and i should get Xemodex to clone it. But I think I should get a second opinion, no offense to the mechanic. (BTW if anyone in the Winston Salem / Greensboro / Triad area needs a great mobile mechanic, I can refer). I'm trying to find the common denominator. It acts like a bad connector or failing relay. maybe even a failing fuse. I can shotgun it - I am close to a parts yard, so I can grab relays and swap out, but I prefer isolating the problem before doing anything.

So what is the common point? Anyone with suggestions?
Much thanks

[azureblue]

And More:
Instrument panel back lights, and back light for headlight switch, won't come on, when the turn signals, window lifts, and wipers stop working. . Headlights will not come on, also. Transmission shifter lock out will not release unless the car is turned off then back on. The lockout is not engaged when ignition switch is at position II and the motor not running. So I can start the car in neutral, at worst.
Car works fine the first maybe 15 minutes of driving from a cold start.

It acts like a bad relay, bad connection, maybe a failing fuse, but I can't figure out the common denominator. I was also wondering if the new alternator could be leaking AC into the system, like a failing rectifier diode. Is there a common relay that handles all of the misbehaving components? One that behaves one way with the ignition switch in II, and another after the car is started?

Otherwise, the car runs great. Starts right up every time, engine behaves perfectly, plenty of "go".

While I don't doubt the mechanic's diagnosis of checking and cloning the CEM, I am hoping there is something that was missed, that acts just like a erratic CEM..

[jonesg]

I hate electronics, but it sounds like a common denominator could be ignition switch.
A long careful look at the circuit diagrams maybe.
If stuff starts going wonky as it warms up under the hood try running it with the hood open, let it come up tp temp and see if anything is failing.

check the elec box cooling fan, if the fan fails the ecm overheats and sends everything nuts. Theres a 5 amp fuse in the engine bay.

[azureblue]

Hm - I'm not sure if I have a fan in the ECM box. IIRC, the readout said things like "low voltage canbus" and a whole list of stuff that didn't add up. He couldn't print out the list for me. I will try with the hood open - good idea... I will test the ignition switch - flipping it on and off when the car acts up, to see if that changes anything..

I'm going to see if my local indy Volvo guy can do a read out and print out. And get the SRS reset while he's in there. He hates electronics, too. I don't like electronics, either, especially computer bus stuff. It could be as simple as a loose wire .. And my Volvo mechanic pored over the schematics from the official shop manual and couldn't figure it out..

I checked the wires to the recently replaced alternator again, and all connectors I may have disturbed, like the 2 sensors on the pipe, (which I seriously doubt have anything to do with the problem. I am going to get the alternator tested today for a failing diode / rectifier.

What bothers me is the car had no problems until the water pump and the intake manifold to intercooler pipe were replaced. And I am pretty sure it started after I replaced the pipe. After the pump was replaced, the car was taken out for a test drive, and there were no problems..

[azureblue]

Volvo mechanic says it's the ignition switch. I hope. At least I'm not far from a parts yard that has a couple of V70s..

[jonesg]

Volvo mechanic says it's the ignition switch. I hope. At least I'm not far from a parts yard that has a couple of V70s..

its a logical suspicious part in the chain of symptoms but its electronics , you never know until you know.
Thank god for pick n pulls, that switch would cost a pretty penny if bought new.

To verify by diagnosis would require diagrams, back probes and a meter/test lights.
Pine hollow has some great videos on this proceedure.

[azureblue]

Of Course it's raining here today. . At least I have an enclosed garage.. Looks like a very easy job to do. Much thanks.
The switch was diagnosed the old fashioned way - bang on the the bottom of the steering column. The reader threw all sorts of codes - I can't see how a person could find the problem just be reading codes... Makes me wish I had my '59 SAAB 2 stroke again..
Where can I find "Pine Hollow"?

[jonesg]

parts cannon vs diagnostics.

[azureblue]

and it was the ignition switch. I was lucky and found a recently replaced one at the parts yard. Simple R&R, like 20 minutes to swap out. Much thanks to all who offered advice...

Now to get the SRS code reset....