94 Camry ECU (Computer) Fault

EVIDINHAJR

MEMBER
1994 TOYOTA CAMRY

I bought this Camry about a year and a half ago with a check engine light on problem. Erratic idle prompted me to take it in to the Dealer for servicing. Dealer diagnosed code 12 and 41. Recommended replacing the distributor, ignition coiil, plug wires and spark plugs, and throttle positon sensor. Check engine light still remained. Erratic operation still continued with addition of intermittant hard starting. Took it to another auto mechanic. Recommended replacing the distributor again. Mechanic did a check of signals sent from the distributor to the computer controlling idle rpm and fuel delivery. Did a wire harness check. Recommended testing and or rebuilding/replacing the main Engine computer (ECM). Sent ECU out to be repaired/rebuilt. Returned with the problem and some new ones. Car now stalss or dies out intermittently when at a stop. Sent ECU back to the rebuilder. Returned with the same problems. Took car to a local auto diagnostic sun center. Tech diagnosed all systems good with the exception of the computer. Distributor, starting/ignition, sensors, grounds systems and the wire harness circuitry are all doing what they are supposed to do whithin specs. How do I verify or correct this possible computer problem when the repair/rebuild folks say that the computer is fixed?

1 Reply

LOSONE

MECHANIC
1,616 POSTS

From the codes you must have the 2.2l as the 3.0 is ODB2

First of all there are no signals from the distributer to the ECU that controls fuel delivery and Engine idle. The ECU does this based on all sensor inputs with the distributer being only one of the signals used.

Code 12 is RPM sent from the distributer to the ECU

Code 41 is the throttle position signal sent to the ECU

There are two different ECU, on is a California and one is other. The RPM signal and TPS signals are used differently in the Calif. ECU.

I suspect you might have a mix up of ECU. I am looking at the schematics now and that is the only thing different and if you have the wrong ECU it will cause those codes to be set.

Let me know