OBD-1 Code 25 "A/F Lean" Question Options

[jasonrobo02]

Hey all,

I've searched and I haven't been able to come up with an answer to what may be causing the CEL on my 1994. The CEL comes on once in awhile. I haven't noticed any change in driveability or gas mileage. The light will go off after turning off the car and will stay off until another "trip condition" occurs maybe 10 or 100 miles later. The code is stored in memory though and will blink a 25 when I jumper the diagnostic port.

I have recently replaced the 02 sensor and no change. I was hoping that someone had some insight as to what may be causing the CEL.

Thanks in advance for any help.

[wrathc5525]

12 ............... No "G", "G1", "G2" or "NE" Ignition Signal To ECM
Within 2 Seconds After Engine Is Cranked,
No "G" Ignition Signal To ECM For 3 Seconds
With Engine Speed Of 600-4000 RPM
Open In "G-" Circuit
13 ............................. No "NE" Ignition Signal To ECM When
Engine Speed Is Greater Than Approximately 1000 RPM,
No "G" Ignition Signal To ECM When "NE" Signal
Is Input 4 Times With Engine Speed Of 600-4000 RPM
14 .................... No "IG" Or "IGF" Ignition Signal To ECM From
Ignitor Several Times In Succession
16 ...................... Fault In Transmission/Transaxle ECU Or ECM
21 .............................. Defective O2 Sensor, Open Or Short
Circuit In O2 Sensor Signal
22 ......................... Open Or Short Circuit In Engine Coolant
Temperature Sensor Signal
24 ......... Open Or Short Circuit In Intake Air Temp. Sensor Signal
25 ............... Lean Signal Sent By O2 Sensor For Several Seconds
26 ............... Rich Signal Sent By O2 Sensor For Several Seconds
27 ................... Open Or Short Circuit In Sub-O2 Sensor Signal
28 ............................................ Defective O2 Sensor,
Open Or Short Circuit In O2 Sensor Signal
31 ................................ Open Or Short Circuit In Airflow
Meter Or MAP Sensor Signal
32 ........... Open Or Short Circuit Between Airflow Meter Terminals
34 ............................... Turbocharger Pressure Is Abnormal
35 ................. Open Or Short Circuit In Turbocharging Pressure
Sensor, MAP Sensor Or BARO Sensor
41 ........ Open Or Short Circuit In Throttle Position Sensor Signal
42 ............................. No Signal From Vehicle Speed Sensor
For Several Seconds
43 ..................... No "STA" Signal To ECM Until Engine Reaches
800 RPM With Engine Cranking
47 .... Open Or Short Circuit In Sub-Throttle Position Sensor Signal
51 ............... (2) Problem In One Of 3 Circuits Monitored By ECM
52 .................... Open Or Short Circuit In Knock Sensor Signal
53 .................................. Knock Control In ECM Is Faulty
55 .................... Open Or Short Circuit In Knock Sensor Signal
71 ................................... EGR Gas Temperature Less Than
Predetermined Level During EGR Control
78 ...................... Open Or Short Circuit In Fuel Pump Control
Circuit Or Fuel Pump Electronic Control Unit (ECU)
81 ................. Open In ECT1 Circuit Between ECM & Transmission
Control Module (TCM) For At Least 2 Seconds
83 ................. Open In ESA1 Circuit Between ECM & Transmission
Control Module (TCM) For 1/2 Second After
Engine Idles At Least 1/2 Second
84 ................. Open In ESA2 Circuit Between ECM & Transmission
Control Module (TCM) For 1/2 Second After
Engine Idles At Least 1/2 Second
85 ................. Open In ESA3 Circuit Between ECM & Transmission
Control Module (TCM) For 1/2 Second After
Engine Idles At Least 1/2 Second
(1) - Listed are possible areas causing trouble codes. Not all
trouble codes are used on all models.
(2) - Throttle position sensor, Park/Neutral switch and A/C Signal
circuits are monitored.

here i hope this helps this is from the service tech manual