First, I want to thank everyone on this forum for the help last year.

I am trying to iron out the rest of my issues. I had loss of power at high rpms last year. I lived with it for quite a while. One day I was washing the engine compartment...the car ran horribly after. I guessed I fouled a cylinder somehow. Ended up finding out the top ignition module was bad. I bought a new one at Advance Auto and the car started running MUCH better. Of course solving this problem has spawned a new one.

Now the car dies occasionally when I am slowing to turn or stop.

I had cleared the codes and now I get the following:

23 - intake air temp sensor low temp ( I will check the wire/sensor)

42 - electronic spark timing circuit

43 - electronic spark control circuit

58 - pass key (disabled I think)

The car runs better than before, but it smells like it might be running rich. I have an exhaust leak...might be the donut gasket. The sound comes from the rear of the engine compartment.

The stalling is the number one problem. The steering gets extremely hard when it stalls...and it could cause an accident. It looks like code 42 is my main issue...where do I check for a ground/open in the "EST CIRCUIT"?

Below is the info I have found so far....I am asking what order I should check components etc...please treat me as an idiot. I have worked under the hood of cars a lot...but not much under this hood. I don't know where sensors are...or what they look like etc.

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CODE 42

Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system.

During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control. The ECM calculates what the timing should be then "tells" the ignition module via the EST circuit.

An open or ground in the EST circuit will stall the engine and set a Code 42. The engine can be re-started but it will run on ignition module timing.

The conditions for setting this code are:

System in BYPASS mode but the ignition module is still controlling timing

- or -
Engine speed > 600 RPM with no EST pulses (ECM controlled timing) going to the ignition module for 200 msec.



Typical causes for this code include:

1) BYPASS line is open or grounded
2) EST line is open or grounded
3) PROM or CALPACK not seated properly in the ECM
4) Poor connections between ignition module and ECM
5) Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise)
6) Faulty or incorrect ignition module
7) Faulty ECM

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CODE 43

Trouble Code 43 indicates that there may be a malfunction in the Electronic Spark Control (ESC) circuit.

ESC is used to sense spark knock (pinging) and retard the timing to eliminate it. A knock sensor (located at the rear of the engine block) sends signals to an ESC module which then signals the ECM that knocking is being detected. The ECM will retard the timing by as much as 20 degrees in 1 degree increments. A loss of knock sensor signal or loss of ground at the ESC module will cause the signal at the ECM to remain high. The ECM will act as if no knock is present, and may possibly result in engine damage, if there is detonation.

Loss of the ESC signal to the ECM will cause the ECM to constantly retard the timing to its maximum. This results in sluggish performance and a Code 43.


The conditions for setting this code are:

Engine is running
ESC input signal has been low more than 2.23 seconds



Typical causes for this code include:

1) Open or shorted knock sensor
2) Loose knock sensor
3) Excessive mechanical noise within engine
4) Improper or incorrectly installed PROM or CALPACK in the ECM or defective ECM
5) Intermittent open in the EST line to the ignition module

That'* all I could have told you.