Hi every one. So like the title says. My check engine light has come on, but no diagnostic trouble code is found? I went down to autozone and had them plug in the scanner, it came up with pass. He told me there is nothing causing the light to come on. It is on though so I headed down to the dealership. They did the same thing with the same result? Has any one had this happen before? How can I fix this. The dealership even went as far as telling me there are not even any pending codes?
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CEL on with no DTC??
- Thread starter outracing
- Start date
8Mud
NAXJA Forum User
- Location
- Central Germany
Did you try disconnecting the battery then going through the reboot (re learn) sequence?
Be real careful disconnecting the battery and try to wiggle arch it as little possible. Open the battery clamps up enough so it goes on smooth and quick in one shot. Arching the battery clamps multiple times cam screw up your voltage regulating program. Same thing can happen at the computer plug.
Be real careful disconnecting the battery and try to wiggle arch it as little possible. Open the battery clamps up enough so it goes on smooth and quick in one shot. Arching the battery clamps multiple times cam screw up your voltage regulating program. Same thing can happen at the computer plug.
birchlakeXJ
NAXJA Forum User
- Location
- Melrose, MN
First, perform the below procedure; for OBDII Jeeps.
This six step procedure will erase the “Adaptive Memory” stored inside the PCM and allow a new “Adaptive Memory” to be developed. After performing this procedure the PCM will re-learn and store into Adaptive Memory your engines performance characteristics.
Perform these steps exactly as they are written, in the order they are written. This will cause the adaptive memory in the PCM to be erased and cause the PCM to go into Fast Learn Mode adaptive mode.
1. Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory.
2. Reconnect the Battery Cable
3. Turn Ignition Switch to the “On” position but DO NOT start the engine
4. Turn Headlight “On”
5. Turn Headlights “Off”
6. Turn Ignition Key “Off”
The PCM Adaptive memory has now been flashed, or erased from the PCM.
When you start the engine it will be running off a set of pre-programmed values that come with the PCM from the factory. When you get the engine up to operating temperature the PCM will start to collect data for the “Adaptive Memory”. The PCM will collect data for Adaptive Memory for the first 50 warm-up Cycles.
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If the above reset procedure doesn't help, I remember seeing a CEL but no actual code only once and it turned out to be a faulty Evap Canister Purge Solenoid. You can check the operation of the solenoid by opening the hood, start the engine, when it warms up the solenoid (located against the firewall, and by your A/C accumulator) will start clicking. If it never starts clicking it could be a bad solenoid, or it could be a lack of a pulse voltage from the PCM to activate the solenoid. The Evap valve/solenoid must be changed as a unit. Check ALL hoses associated with the charcoal canister and evap system while you are at it.
Good luck and be sure to keep us posted!!
This six step procedure will erase the “Adaptive Memory” stored inside the PCM and allow a new “Adaptive Memory” to be developed. After performing this procedure the PCM will re-learn and store into Adaptive Memory your engines performance characteristics.
Perform these steps exactly as they are written, in the order they are written. This will cause the adaptive memory in the PCM to be erased and cause the PCM to go into Fast Learn Mode adaptive mode.
1. Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory.
2. Reconnect the Battery Cable
3. Turn Ignition Switch to the “On” position but DO NOT start the engine
4. Turn Headlight “On”
5. Turn Headlights “Off”
6. Turn Ignition Key “Off”
The PCM Adaptive memory has now been flashed, or erased from the PCM.
When you start the engine it will be running off a set of pre-programmed values that come with the PCM from the factory. When you get the engine up to operating temperature the PCM will start to collect data for the “Adaptive Memory”. The PCM will collect data for Adaptive Memory for the first 50 warm-up Cycles.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
If the above reset procedure doesn't help, I remember seeing a CEL but no actual code only once and it turned out to be a faulty Evap Canister Purge Solenoid. You can check the operation of the solenoid by opening the hood, start the engine, when it warms up the solenoid (located against the firewall, and by your A/C accumulator) will start clicking. If it never starts clicking it could be a bad solenoid, or it could be a lack of a pulse voltage from the PCM to activate the solenoid. The Evap valve/solenoid must be changed as a unit. Check ALL hoses associated with the charcoal canister and evap system while you are at it.
Good luck and be sure to keep us posted!!
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