Ecu codes?

My check engine light came on a few days ago and I just got around to having it scanned today. There are 2 error codes: P0125 and P0170. Apparently it's something with closed loop fuel trim..?? Also, the engine coolant temperature sensor, as well as the o2 sensor could be the problem (according to autozone). I remember reading somewhere that the ecu adjusts fuel trims once the car warms up, so if the engine coolant temp sensor is bad, then it wouldn't adjust fuel trims and throw a CEL, this correct? Also, seeing as how it wouldn't adjust fuel trims, it makes sense that I wouldn't be making as much power as I should, correct? :mad:

ANYWAYS, my question is: is there any way I can check to make sure exactly what the problem is, instead of buying a new o2 sensor and coolant temp sensor? Also, is there a website that lists all the error codes and what is most likely the problem? Thanks!

p0125= insufficient coolant temp for closed loop fuel control
p0170= fuel trim malfunction (bank no.1)
I got most of the mitsu DTC codes so if u got anymore n wanna find out what they me just let me kno

I see, how do you have most of the codes? I want them! ;)

So it seems like the engine coolant temp sensor could very well be the problem, since I am getting a fuel trim malfunction in closed loop (which is not WOT, right?). I'd like it if someone else could back my thoughts up, since I will most likely be having someone do a full diagnostic tomorrow if I can't figure out what it is! :( Where are ya kev! ;)

Trouble Codes - 1995- 1997 Models (using Check Engine Light)
note: Not all trouble codes apply to all models.

Code 11..... Intermittent loss of crankshaft and/or camshaft position sensor signals to PCM, complete loss of crankshaft position sensor signal to PCM, or timing belt skipped one or more teeth

Code 13..... Problem with the MAP sensor circuit
Code 14..... MAP sensor voltage out of normal range
Code 15..... A problem with the Vehicle Speed Sensor Signal. No Vehicle speed sensor signal detected during road load conditions.
Code 16..... No input signal from knock sensor.
Code 17..... Engine is cold to long. Engine coolant temp remains below normal operating temp during initial operation (check Thermostat)
Code 21..... Problem with the upstream oxygen sensor signal circuit. Sensor voltage to computer not fluctuating.
Code 22..... Engine coolant temp sensor voltage out of normal range
Code 24..... Throttle position sensor voltage high or low. Test the Throttle position sensor.
Code 25..... Idle Air Control (IAC) motor circuits. A shorted condition is detected in one or more of the IAC motor circuits.
Code 27..... One of the Injector control circuit output drivers does not respond properly to the control signal. Check the Circuits.
Code 31..... EVAP system fault.
Code 32..... An open or shorted condition detected int he EGR solenoid circuit. Possible air/fule ratio imbalanc not detected during diagnosis.
Code 35..... Open or shorted condition detected in the radiator fan high or low speed relay circuits
Code 36..... Pulsed secondary air injection system problem (95 manual transaxle only)
Code 37..... Transaxle PARK?NEUTRAL switch failure
Code 42..... Fuel pump relay of MFI (ASD) relay control circuit indicates an open or shorted circuit conditon.
Code 43..... Misfire on one or more cylinders detected. Spark plug, injector, cylinder compression or air intake problem; primary circuit problem in one or both ignition coils
Code 45.....Transaxle fault present in transmission control module - Automatic transaxles
Code 46..... Charging system voltage too high. Computer indicates that the battery voltage is not properly regulated
Code 47.....Charging system voltage too low. Batter voltage sensor input below target charging voltage during engine operation and no significant change in voltage detected during active test of alternator output.
Code 51..... Oxygen sensor signal input indicates lean fuel/air ratio condition during engine operation.
Code 52..... Oxygen sensor signal input indicates rich fuel/air ratio condition during engine operation.
Code 53..... Internal PCM failure detected
Code 54..... No camshaft position sensor signal. Problem with the sensor or circuit.
Code 62..... Unsuccessful attempt to update EMR mileage in the PCM EEPROM. PCM failure
Code 63..... Controller failure. EEPROM write denied. Check the PCM
Code 64..... Catalytic converter efficiency below required level
Code 65..... Power Sterring switch failure detected
Code 66..... Transmission control module (TCM) not sensed by PCM.

Trouble Codes - Using scan tool
NOTE: these are "generic" trouble codes and pertail to all modes (95-01)

P0102..... Mass airflow (MAF) sensor circuit low input
P0103..... Mass airflow (MAF) sensor circuit high input
P0106..... Barometric pressure out of range
P0107..... Manifold Absolute Pressure (MAP) Sensor Voltage too low
P0108..... Manifold Absolute Pressure (MAP) Sensor Voltage too high
P0112..... Intake Air Temp (IAT) sensor circuit low input
P0113..... Intake Air Temp (IAT) sensor circuit high input
P0117..... Electronic Coolant Temp (ECT) sensor circuit low input
P0118..... Electronic Coolant Temp (ECT) sensor circuit High input
P0121..... In range Throttle Position Sensor (TPS) fault
P0122..... Throttle Position Sensor (TPS) circuit low input
P0123..... Throttle Position Sensor (TPS) circuit high input
P0131..... Upstream heated O2 sensor circuit low voltage (Bank 1)
P0132..... Upstream heated O2 sensor shorted to voltage
P0133..... Upstream heated O2 sensor circuit slow responce (bank 1)
P0135..... Upstream heated O2 sensor heater circuit fault (bank 1)
P0136..... Downstream heated O2 sensor fault (Bank 1)
P0138..... Downstream heated O2 sensor shorted to voltage
P0140..... Downstream heated 02 sensor neather rich or lean cond detected
P0141..... Downstream heated O2 sensor heater scircuit fault (bank 1)
P0151..... Upstream heated O2 sensor circuit low voltage (Bank 2)
P0153..... Upstream heated O2 sensor heater circuit slow response (bank 2)
P0155..... Upstream heated O2 sensor heater circuit fault (bank 2)
P0156..... Downstream heated O2 sensor fault (bank 2)
P0161..... Downstream heated O2 sensor heater circuit fault (Bank 2)
P0171..... System Adaptive fuel too lean (bank 1)
P0172..... System Adaptive fuel too rich (bank 1)
P0174..... System Adaptive fuel too lean (bank 2)
P0172......System Adaptive Fuel too rich (bank 2)
P0191..... Injector Pressure sensor system performance
P0192..... Injector pressure sensor circuit low input
P0193..... Injector Pressure sensor circuit high input
P0201..... Injector No.1 output driver not responding properly
P0202..... Injector No.2 output driver not responding properly
P0203..... Injector No.3 output driver not responding properly
P0204..... Injector No.4 output driver not responding properly
P0205..... Injector No.5 output driver not responding properly
P0206..... Injector No.6 output driver not responding properly
P0300..... Multiple cylinder misfiring detected
P0301..... Cylinder No.1 Misfire detected
P0302..... Cylinder No.2 Misfire detected
P0303..... Cylinder No.3 Misfire detected
P0304..... Cylinder No.4 Misfire detected
P0305..... Cylinder No.5 Misfire detected
P0306..... Cylinder No.6 Misfire detected
P0325..... Knock sensor circuit fault
P0326..... Knock sensor circuit performance
P0351..... Ignition coil no.1 primary circuit fault
P0352..... Ignition coil no.2 primary circuit fault
P0353..... Ignition coil no.3 primary circuit fault
P0354..... Ignition coil no.4 primary circuit fault
P0355..... Ignition coil no.5 primary circuit fault
P0356..... Ignition coil no.6 primary circuit fault
P0400..... EGR flow Fault
P0401..... EGR insufficient flow detected
P0402..... EGR excessive flow detected
P0403..... EGR transducer circuit open or shorted
P0420..... Catalyst system efficiency below threshold (bank 1)
P0421..... Catalyst system efficiency below threshold (bank 1)
P0430..... Catalyst system efficiency below threshold (bank 2)
P0431..... Catalyst system efficiency below threshold (bank 2)
P0442..... EVAP small leak detected
P0443..... EVAP VMV circuit fault
P0452..... EVAP Fuel tank pressure sensor low input
P0453..... EVAP fuel tank pressure sensor high input
P0455..... Leak in EVAP system detected
P0462..... Fuel level sending unit - Low voltage indicated
P0463..... Fuel level sending unit - High voltage indicated
P0460..... Fuel level sending unit - no movemnet detected
P0500..... VSS fault
P0505..... IAC valve system fault
P0600..... PCM internal fault
P0601..... PCM internal fault
P0603..... PCM Keep Alive Memory test error
P0605..... PCM Read Only Memory test error
P0622..... Alternator field circuit open or shorted
P0645..... A/C clutch realy circuit open or shorted
P0700..... Automatic transmisson fault detected
P0703..... Brake switch stuck open or closed.

You definitely will want your engine coolant temp sensor working--you could blow your engine or every gasket in it if it's not! Does the temp. rise at all when you drive?

Guess im lucky with my 1g, all i do is hook a voltmeter to the "diagnostic" port and it gives me the long or short holds! :loser:

Thanks Joematthews! And yes, the temp gauge does rise as the car warms up, and it stays right near the middle all the time and I've never seen it go above that point.

Nevermind, after doing a lot of reading on dsmtuners I learned that on the 95's, those codes really mean that the o2 sensor is bad. Thanks for all the help though! :)

i got a problem with the o2 sensor bank 1 sensor 2 and also the sensor that feeds the ecu for the coolant temp. They were telling me that if i fix one it would maybe eliminate the other problem. so which one should i do.

ok yesterday i cleaned my throtle body and after i was done, i started my car, and engine light came on, i checked the codes with the engine light, it gave me code 12,24,25 i just read what 24, and 25 mean, but still don't know what 12 is, anyone in here knows?also,any ideas of what might be wrong with my car 'cause it was fast when i got it, but now it's still fast but not as much, i thought it could be
ignition coil
spark plug wires, or throtle body , that's why i cleaned it ,
anyone plz help, thanks in advance,

Nevermind, after doing a lot of reading on dsmtuners I learned that on the 95's, those codes really mean that the o2 sensor is bad. Thanks for all the help though! :)


I am going to disagree with your conclusion, sorry :mad:

Getting a DTC of p0125= insufficient coolant temp for closed loop fuel control, is letting you know that the car is not warming up, according to the ECU. It is therefore running in "limp mode" which is very rich. This is then causing the FT DTC because of running so rich.

Also, just because your coolant temp gauge is reading normally, don't assume the ECU is receiving the correct information. There are actually 2 coolant temp sensors. :naughty: One supplying information to the gauge and the other to the ECU.

I had the same two DTC's last year and ended up having to replace my coolant temp sensor. The "sure-fire" way to tell, is take a look at the coolant temp on a logger. If the sensor is bad you will get a reading of
-40 degrees (if I remember correctly).

I think the sensor is $26 from the dealer.