MALF 41: EST Open

this is the error code my datamaster is giving me

The car is a 95 z28 and I just had a local shop replace the opti-cap and rotor and they also replaced the ignition control module. The car seems to run fine, but needless to say I wasn't happy to pick the car up and see a service engine light. The shop doesn't have an OBDI reader so I'm having to look into it myself.

Can anyone offer insight into what this trouble code is telling me?

 

Hopefully it's a residual fault from them working on the car. DTC 41 is usually is an open wire from the PCM to the ICM or a defective ICM. The code will shut down the fuel injectors to prevent flooding as the car should not have any spark if that circuit is defective. Since you are running fine, it's probably an old DTC from them playing around with the ignition. Reset the DTC and see if it comes back, if it does, and they put in a new ICM, I would suspect they broke something, you have a loose connection or new defective ICM.

 

Further developments...

I have an MSD 6AL box on the car and when I take it out of the loop, things change a bit. With the MSD box connected, the SES light comes on within 5 seconds of firing the car up and stays on constantly. With the MSD box disconnected, the SES light turns off when the car is idling but comes back on within 5 seconds of applying any amount of throttle.

I'm thoroughly confused.

Although the ign control module was replaced when the opti cap and rotor were replaced, I'm thinking it may be a faulty module.

Another thought...the Optima battery has seen some abuse lately with being run down and recharged improperly...could a low voltage supply be causing weird electrical faults?

Keep in mind that the car is running. It seems to stumble and surge a bit at part throttle, but WOT seems fine.

I have made some datalogging runs using datamaster if anyone thinks that may help.

Thanks for any suggestions/advice!

--Jason

 

update

replaced "new" icm with an icm from the dealership...problem went away