1990 Reatta Coupe: Cannot read engine codes

[Reatta2drive]

This is a constant issue we've been having since purchasing the car. Following the reatta.net instructions on reading codes for the 1990 model it just flashes once and doesn't do anything else. Since then we have replaced the ECM, no change. We have not been able to find the correct BCM for sale anywhere.

 

In the meantime we purchased a Red Devil River ALDL connector and have been attempting to use the Tuner Pro RT software to read the codes but it has been showing some majorly erratic data.

 

Any advice on where to go from here?

 

If it helps, the car failed to pass SMOG, it had double over the max value of NO. So it is due for a new catalytic converter.

[2seater]

I am not familiar with the Reatta.net code reading instructions? Is it for shorting the aldl and reading flashes or is it to access the onboard diagnostics through the climate control head??  Is the check engine light indicating there are codes during normal driving??

[rogold99]

Does your ALDL connector have the cover installed when you are trying to read the codes using the dash?  It needs to be on according to these instructions: Reatta Owners Journal  

 

If you are trying to read ABS codes, this says to short pins A and H for a 1990 Reatta

Edited May 17, 2021 by rogold99 (see edit history)

[Reatta2drive]

Apologies, the code reading instructions we followed were from https://www.reattaowner.com/roj/onboard-diagnostics/how-to-access-trouble-codes#2-how-to-access-the-codes-for-90-91-models not reatta.net

 

 

Yes, the ALDL cover was on. The check engine light only pops up at idle, such as at a stop light or after warming up. Once you get moving it shuts off.

[rogold99]

    Can you measure battery voltage,  before and after starting the car. Kinda sounds like it is idling too low to create the roughly 13.3 volts, or the voltage regulator in the alternator may be bad. Also sometimes when the voltage regulator goes bad, it will create a AC voltage which can mess with computer systems. 

     It may be easiest to remove the alternator and have it tested at a auto parts store.  Luckily, it is easy to remove on a Reatta.

 

[padgett]

Might just need a new O2 sensor. OK, to read diagnostics you turn the key to run (do not need to start) and hold the climate control OFF and WARMER in at the same time until the dash blinks. If your Climate Control panel is not working the buttons may need to be cleaned.

 

If the engine starts and the dash works, ECM and BCM are probably working.

[Reatta2drive]

In the next few days we will read the voltage and test that. The climate control does work, and when trying to enter diagnostics the dash flashes but I am unable to scroll or receive codes. I'll take of video of trying to enter diagnostics before I test the voltage and probably grab an O2 sensor sometime this week.

 

Thanks for the replies everyone! I'll keep you updated.

[Jim]

Occasionally not being able to read the codes from the ECC/IPC is a  bad IPC.

Over the years I have seen on several occasions where the IPC will work correctly in all functions but when trying to read the codes by pressing the buttons on the ECC, the system will start to function like it should but will not complete the task because there is a problem in the IPC. 

Before I sell an IPC I always check to make sure all the 12V indicator bulbs light up and the four switches do their thing and on the '90-91 IPCs I make sure it will go to diagnostics.

I also test them for a minimum of 30 days in my personal car to make sure they are not intermittent.

I do not, at this time, have any good '90-91 IPCs available.

[Reatta2drive]

Thank you for the ipc idea I will definitely try it! update so far is that I have replaced the o2 sensor and the car has 7 miles on it after a new catalytic converter. However I still have a check engine light. I still need to check the voltage but I unplugged the battery after the o2 sensor change to reset codes and I still got one. I will look for an ipc and work on the voltage and update again. Thank you all for the support.