Strange ECU error code

[geeaj]

My 89 s13 is having a problem with the check engine light. It came on after I replaced the alternator and put in a new battery.

I pulled the ecu and read the code, it returned code 55. So I figured this was some sort of a once in a blue moon occurance. Having said that, I reset the ECU. The light cleared.

I drove it for a day and the light came back on several hours later. The car is running great (as great as can be for a 175K car =P). I didn't notice any changes in performance, although my mileage seems to be degrading. I have used up a quarter tank and only show 80miles elapsed on the gauge.

I've recently changed the following:

spark plug wires
basic tune up, includes air filter, crackcase filter, oil filter, fuel filter
MAF
head temperature sensor
coolant temperature sensor
water pump
thermostat
oxygen sensor
alternator
battery

What do you think could be causing this problem? Bad engine/chassis ground? Bad ecu? I mean, the car runs fine but hate that #### light!

Any help would be appreciated...

maybe this will help? :confused:
Code # Description

12 Air flow meter circuit
13 Engine temperature sensor circuit
14 Vehicle speed sensor circuit
31 E.C.U. (E.C.C.S. control unit)
32 EGR function
33 Exhaust gas O2 sensor circuit
35 Exhaust gas temperature circuit
43 Throttle position sensor circuit
45 Injector leak

For Non-California Models:

RED L.E.D. ON = The ECU's CPU or the Crank Angle sensor is malfunctioning.

__________________________________________________ ____

Mode II (Engine OFF)- Stored Self Diagnostic Results

Code # Description

11 + Crank angle sensor circuit
12 E Air flow meter circuit
13 E Engine temperature sensor circuit
14 E Vehicle speed sensor circuit
21 + Ignition signal circuit
31 E E.C.U. (E.C.C.S. control unit)
32 * E EGR function
33 E Exhaust gas O2 sensor circuit
34 Detonation sensor circuit
35 * E Exhaust gas temperature circuit
43 E Throttle position sensor circuit
45 * E Injector leak
54 Signal circuit from A/T control unit to ECU (A/T only)
55 No malfunction in the above circuits

[geeaj]

Thanks for the code chart, but the code returned was 55. So it leads me to believe that nothing is wrong, however the light still comes back on.

I may disconnect the battery for more then 12hrs to do a *hard* reset.

[96SEChick]

If your CEL keeps coming on, but it's throwing a 55 code, I would actually suggest taking it to the shop.  There's something odd that's making your CEL come on.  Mine came on once after I bogged the car one night, but was throwing a 55, and it never came back on after I reset it.  Has this been happening since you replaced the O2 sensor or the MAF?  Or was it happening before?  It seems that maybe one of the parts you replaced needs to be adjusted or is possibly faulty, since you're commenting on bad gas mileage also.

[whateverjames]

ouch code 55 that's gonna cost you.  actually i could have swore 55 means every thing is gonna be alright. everything's gonna be alright now, everything's gonna be alright.

[geeaj]

I know this is really strange. I am going to try to reset the ecu again and see what happens. Also, when I do the reset procedure, does the screw have to be returned to the fully clockwise position?

[boycelaforest707]

I know this is really strange. I am going to try to reset the ecu again and see what happens. Also, when I do the reset procedure, does the screw have to be returned to the fully clockwise position?

55 IS "NO ERROR CODES"
Fuck dead thread, threads older than 1 year should be archived, wtf.

[drifter808]

or you should just not bring them back up!!!