Code 25,26
02-23-11, 08:03 PM
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Code 25,26
My car has been throwing those 2 codes every now n then most threads ive read ppl say its the upstream O2 sensor.
The codes come n go n when the cel is on I get lean idle around 15.2 - 16.3 n the car shakes a bit n when crusing on the highway its in between 14.9-15.6 and dips into 16.2 for a half second every few seconds but it usually fixes itself after awhile the cel goes away and afr goes back to normal....is this a bad O2? Anyone with this off n on thing before?
The codes come n go n when the cel is on I get lean idle around 15.2 - 16.3 n the car shakes a bit n when crusing on the highway its in between 14.9-15.6 and dips into 16.2 for a half second every few seconds but it usually fixes itself after awhile the cel goes away and afr goes back to normal....is this a bad O2? Anyone with this off n on thing before?
02-23-11, 08:47 PM
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I am sure yo already know this, but code 25 is Air fuel ratio lean malfunction and code 26 is air fuel ratio Rich malfunction.
You should do the o2 sensor check. Warm up the engine. Run a 2500 rpms for 120 seconds. Jumper e1 and te1. Maintain 2500 rpm,s and check dc voltage between vf1 and e1 and vf2 and e1. Yo need a least 8 voltage changes in 10 seconds. That means the sensor is working properly.
Now let me tell you about my experience. I did the above test and my voltmeter was stuck right at 5 volts. No movement. Follow the troubleshooting chart and it basically lead to a lean condition. My fuel pump ECU was not working properly at low speed. I jumpered fp and +b to put the pump in constant high speed, bypassing the ECU than conducted the o2 sensor check again and now my sensors were doing a nice steady pulse. The engine coolant temp sensor also figures into this. If you would like I can post some screen shots from the fsm for this check and the troubleshooting flow chart.
Basically if you check the voltage on the o2 sensors and you read 0 or 5 volts you know you have a problem. I would check that and go from there.
You should do the o2 sensor check. Warm up the engine. Run a 2500 rpms for 120 seconds. Jumper e1 and te1. Maintain 2500 rpm,s and check dc voltage between vf1 and e1 and vf2 and e1. Yo need a least 8 voltage changes in 10 seconds. That means the sensor is working properly.
Now let me tell you about my experience. I did the above test and my voltmeter was stuck right at 5 volts. No movement. Follow the troubleshooting chart and it basically lead to a lean condition. My fuel pump ECU was not working properly at low speed. I jumpered fp and +b to put the pump in constant high speed, bypassing the ECU than conducted the o2 sensor check again and now my sensors were doing a nice steady pulse. The engine coolant temp sensor also figures into this. If you would like I can post some screen shots from the fsm for this check and the troubleshooting flow chart.
Basically if you check the voltage on the o2 sensors and you read 0 or 5 volts you know you have a problem. I would check that and go from there.
03-05-11, 05:48 PM
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Tested the o2 they seem to work fine bought a new bosch one n wired it up just to see, reset the ecu she ran like champ around town around 14.7 cruise and idle came home took the car out again n then it seemed to run rich idle at 13 and cruise at 12.3... Cel comes back I stopped at a store started it again idles at 16.7 cruises at 15...... Before I put in the new o2 every time I reset the ecu it would run awesome for awhile and then act up... Any more ideas?? Driving me nuts
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03-06-11, 05:41 PM
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So I haven't been resetting the ecu and just been noting three pattern. It seems every time I start the car it will run the lean side then shut it off and start it again it will run rich. Always alternating every time I start the car.
but I was going to try and change out my thermostat sometime soon and see if that helps
03-08-11, 12:49 PM
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Yes. By jumping the fuel pump in the diagnostic connector you are accomplishing the same thing as cutting the wires on the ECU and soldering them together. Was a good way to test for awhile before taking the drastic step of actually cutting wires, which I did end up doing.
03-08-11, 12:53 PM
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Tested the o2 they seem to work fine bought a new bosch one n wired it up just to see, reset the ecu she ran like champ around town around 14.7 cruise and idle came home took the car out again n then it seemed to run rich idle at 13 and cruise at 12.3... Cel comes back I stopped at a store started it again idles at 16.7 cruises at 15...... Before I put in the new o2 every time I reset the ecu it would run awesome for awhile and then act up... Any more ideas?? Driving me nuts
03-08-11, 12:55 PM
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Before swapping ecus, tr changing the ECT sensor out. It's on the front of the engine in front of the passenger side coil pack. Remove your plastics and the lower wire tray. Its a larger green plug.
03-08-11, 02:50 PM
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ect my car is a 5sp dont think it has one of those
yeah i think im just going to change out my thermostat here pretty soon like you said its not very expensive.
the values are from my wideband o2 sensor for AFR
aem ems in a couple weeks if everything works out! so i want to fix this pesky problem before then : /
yeah i think im just going to change out my thermostat here pretty soon like you said its not very expensive.
the values are from my wideband o2 sensor for AFR
aem ems in a couple weeks if everything works out! so i want to fix this pesky problem before then : /