Weird computer issue
Thread Starter
Racer
Joined: Sep 2005
Posts: 304
Likes: 1
From: Carson City Nevada
Weird computer issue
HI Guys, my 86 is acting a little weird on my scanner. It is throwing a 41 code ESC. Also in the history of codes are 32(cleaned the MAF and it went away), and a 42. The weird part is the RPM's step in 300rpm increments up to 4500rpm's then go back to 300. Just loops like that. The TPS reads 0 volts and the vehicle speed is 5mph. The O2 voltage is way off as well. The car runs good, the TPS has the correct voltage at the sensor and the RPM gauge works fine. Could the ESC module cause this stuff or is it just a ghost code. I thought it might be the ECM so I swapped it and got the same readings. Any thoughts?
Thread Starter
Racer
Joined: Sep 2005
Posts: 304
Likes: 1
From: Carson City Nevada
Well out of frustration, I reconfigured my scanner for a 87 with the same VIN numbers, everything came up and looks good. I guess my scanner didn't like the 86 and scrambled the data. Now to chase the 41 code.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
According to my notes, error code 41 is "cylinder select error". The 1227165 ECM can be configured for 4, 6 or 8 cylinder engines. That is done by connecting ground to various ECM pins. If the ground is open on pin D3 and/or D10 you will get this error.
Error code 43 is an ESC error. There are two parts to this error (why they didn't give them different numbers is a mystery). When you first start the engine the ECM advances the spark an extra 20°, which causes knocks. After it sees at least two knocks is retards the spark back to its normal value. If it DOESN'T see at least two knocks it sets error code 43.
The ECM will also set error code 43 if the knock sensor module output gets stuck at less than 6 volts for at least 4 seconds. It should be about 9 volts unless it is seeing knocks.
Error code 43 is an ESC error. There are two parts to this error (why they didn't give them different numbers is a mystery). When you first start the engine the ECM advances the spark an extra 20°, which causes knocks. After it sees at least two knocks is retards the spark back to its normal value. If it DOESN'T see at least two knocks it sets error code 43.
The ECM will also set error code 43 if the knock sensor module output gets stuck at less than 6 volts for at least 4 seconds. It should be about 9 volts unless it is seeing knocks.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
http://home.earthlink.net/~cliff_har...s/pinouts.html
Thread Starter
Racer
Joined: Sep 2005
Posts: 304
Likes: 1
From: Carson City Nevada
I assume you mean the connectors on the ECM, so here ya go:
http://home.earthlink.net/~cliff_har...s/pinouts.html
http://home.earthlink.net/~cliff_har...s/pinouts.html
Thread Starter
Racer
Joined: Sep 2005
Posts: 304
Likes: 1
From: Carson City Nevada
Looks like I found the problem. Someone ran a wire from the ground side of the A/C clutch to the block. The compressor was on all of the time and I am assuming grounding out the ECM or something. Anyway, no more check engine light or codes so far.
