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Hello there
i have an 86 C4 with L98 which is having some weird electronic issues (you don't say!). What worries me is the situation is worsening as time passes, and i suspect what i'm experiencing are just symptoms of a larger issue.
My suspect is that ECM is slowly failing. I have a spare one but i don't want to change it if unnecessary and i don't absolutely want to risk this spare one to possibly fail like the current one. I read on the FSM that solenoids and relays are turned on/off by ECM using internal drivers, and failure of one of the drivers may damage other ones. In particular solenods and relay coil resistances must measure more than 20ohms, or can damage drivers.
FSM has a schematic for solenoids (i found only 4) i have a multimeter but i cannot disconnect the 46 C100 connector as it's glued.
I would like to kindly ask you if you have any suggestion on the matter, and if there's another way to get to the solenoids and relays, i can't figure out where they are physically located.
Here's the list of failed stuff, in chronological order:
MPG consumption indicator never worked because of absence of serial communication: i detected no voltage changes on ALDL pin E, stays steady to 5V while should change between 2 and 5 V. I've checked cabling for continuity between ALDL port and ECM and it's ok.
Got code 44 with high idle (900-1100 rpm) when manouvering it to put the car in the garage after a trip. This used to work correctly. BTW car doesn't have catalytic converter.
Car recently died once when idling at traffic light. Dunno if this might happen randomly and it's pretty normal or could be related to other issues.
Paperclip method to enter diagnostic mode is not working. This used to work correctly.
Apart from that, car is working good. It starts and it drives ok.
The 4 solenoids are air switch, air control, both at the front of the engine near the MAF sensor. The other 2 are EGR near the thermostat and purge control at the charcoal canister in the left front wheel well.
You need to verify you have data at Pin E, A meter will not do it.
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L98 solenoid checking
any way to get to the solenoids and relays?
