weird ECM problem? Can't clear codes, expected codes not there

99 XJ, 4.0 automatic

Ok, so I got my scanguage today. Im getting two codes P0204 and P0000

P0000 I imagine is nothing

P0204 is Injector #4 Control cirtcuit " Injector #4 or INJ 4 bank output driver stage does not respond properly to control signal.

Truck runs fine and gets pretty decent mileage. My question is why do I have this code, I also cannot clear it, if I clear it with the scanguge it comes right back.

And also, I no longer have the after cat 02 sensor. The wires got torn out by the driveshaft, its no longer plugged in or existant. Wouldnt I have a O2 sensor and cat converter efficency code?

Seems like you should get the 02 codes. For the injector code, you could swap injector locations to see if it moves. Also check your spark plugs to see if #4 still looks like the other ones. This would at least let you feel safe that #4 wasn't running way to lean which could possibly burn a valve.

I agree with winterbeater here. I've never head of P0000 and from a quick search, it may be an end of list or something that isn't indicative of an actual failure. You do need to resolve the P0204 code though and spark plug and injector are suspect here.

Don't know why you aren't getting an 02 code. Anyone??

I have Innovate's LM-2 and when there is a CEL, I have to scroll through about 8 p0000s until I see a real code--PIA and I haven't bugged them about it yet(I'll check the site and see if there is a newer firmware). So I wouldn't worry about that. I would, however, go to the nearest advanced auto or autozone and get them to use a scanner to double check that other code and see if it clears. Also, I have ran with a hollowed cat and did not get a code from the 2nd sensor.

P0204 Fuel Injector 4 Control Circuit Malfunction

Possible CausesSetting Conditions

• Fuel injector 4 connector is damaged (check pins for damage, and moisture)
• Fuel injector 4 control circuit is open, shorted to ground or shorted to voltage
• Fuel injector 4 power circuit from the ASD relay is open
• Fuel injector 4 has failed
• PCM has failed

Engine speed less than 3,000 rpm; ASD relay "on", injector pulsewidth less than 10 ms, system voltage more than 12.0v, and the PCM did not detect any inductive spike from the injector for 0.18 ms after it is turned off. Note: This code takes 0.64-10 seconds to set once the injector is off.

This code sets in 1 Trip(s).
This code will turn on the MIL (Malfunction Indicator Lamp)

Malfunction Indicator Lamp
The Malfunction Indicator Lamp (MIL) alerts the driver that the Powertrain Control Module (PCM) has detected an OBD II emission-related component or system fault. When this type of malfunction occurs, an OBD II Diagnostic Trouble Code (DTC) will be set by the PCM. The MIL is located on the instrument cluster and is labeled CHECK ENGINE, SERVICE ENGINE SOON, or is identified with an ISO standard engine symbol (i.e., a picture of an engine).
Bulb Test
Each time the ignition switch is turned to the "on" position, the MIL indicator is illuminated for about 3 seconds (which is a function of the PCM).
MIL Lamp-On Message
Each time the PCM detects an Emissions related fault, the MIL is illuminated to inform the driver that the vehicle needs to be taken in for service.




COMPONENT MONITOR DRIVE CYCLE INSTRUCTIONS

• Do not turn off the ignition switch during the test procedure.
• All Onboard System Readiness codes are cleared if the battery is disconnected or when the Powertrain Control Module (PCM) is cleared with the scan tool.
• This drive cycle can be used to determine if the Readiness code for this Monitor will run and complete, and if the Malfunction Indicator Lamp (MIL) will remain off after the vehicle is driven.
• Operating Ranges: Whenever a range of values is provided, try to operate the vehicle in the middle of the range. For example, if the vehicle speed range is from 45-65 MPH, operate the vehicle at as close as possible to 55 mph. If the Short Term fuel trim range is -20% to +20%; try to operate the vehicle near 0%.
• Scan Tool Data: There are certain Parameter Identification (PID) values that must be within range before this Monitor will "run". It can be helpful to pull up those PID items on the scan tool so an assistant can view them during the test.
• The Readiness code for this Monitor defaults to "continuous" or "monitoring" because this Monitor runs continuously when the engine is cranking or running.
• This information is a representation of a Drive Cycle, and may vary due to software revisions to the PCM.

COMPONENT MONITOR PRETEST CONDITIONS

• MIL is off.
• Battery voltage between 11-16v.
• Key on or engine running at idle or cruise speed.

TEST PROCEDURE

1. Connect the Scan Tool to the data link connector (DLC).
2. Start the engine and allow it to run at idle speed for 1-2 minutes.
3. Accelerate at part-throttle to Cruise speed and maintain that speed for several minutes. Bring the vehicle to a stop, but do not turn off the ignition key.
4. Check for any diagnostic trouble codes (DTC's) in memory. If any DTC's are set, refer to the appropriate trouble code chart to make the repair. If no DTC's are set, the test is finished. Return to the service bay and turn off the ignition key.

By the ay this is NOT from any FSM, so it is not copywrite infringement.

silent_bob said:

P0204 Fuel Injector 4 Control Circuit Malfunction

Possible CausesSetting Conditions

• Fuel injector 4 connector is damaged (check pins for damage, and moisture)
• Fuel injector 4 control circuit is open, shorted to ground or shorted to voltage
• Fuel injector 4 power circuit from the ASD relay is open
• Fuel injector 4 has failed
• PCM has failed

Engine speed less than 3,000 rpm; ASD relay "on", injector pulsewidth less than 10 ms, system voltage more than 12.0v, and the PCM did not detect any inductive spike from the injector for 0.18 ms after it is turned off. Note: This code takes 0.64-10 seconds to set once the injector is off.

This code sets in 1 Trip(s).
This code will turn on the MIL (Malfunction Indicator Lamp)

Malfunction Indicator Lamp
The Malfunction Indicator Lamp (MIL) alerts the driver that the Powertrain Control Module (PCM) has detected an OBD II emission-related component or system fault. When this type of malfunction occurs, an OBD II Diagnostic Trouble Code (DTC) will be set by the PCM. The MIL is located on the instrument cluster and is labeled CHECK ENGINE, SERVICE ENGINE SOON, or is identified with an ISO standard engine symbol (i.e., a picture of an engine).
Bulb Test
Each time the ignition switch is turned to the "on" position, the MIL indicator is illuminated for about 3 seconds (which is a function of the PCM).
MIL Lamp-On Message
Each time the PCM detects an Emissions related fault, the MIL is illuminated to inform the driver that the vehicle needs to be taken in for service.

COMPONENT MONITOR DRIVE CYCLE INSTRUCTIONS

• Do not turn off the ignition switch during the test procedure.
• All Onboard System Readiness codes are cleared if the battery is disconnected or when the Powertrain Control Module (PCM) is cleared with the scan tool.
• This drive cycle can be used to determine if the Readiness code for this Monitor will run and complete, and if the Malfunction Indicator Lamp (MIL) will remain off after the vehicle is driven.
• Operating Ranges: Whenever a range of values is provided, try to operate the vehicle in the middle of the range. For example, if the vehicle speed range is from 45-65 MPH, operate the vehicle at as close as possible to 55 mph. If the Short Term fuel trim range is -20% to +20%; try to operate the vehicle near 0%.
• Scan Tool Data: There are certain Parameter Identification (PID) values that must be within range before this Monitor will "run". It can be helpful to pull up those PID items on the scan tool so an assistant can view them during the test.
• The Readiness code for this Monitor defaults to "continuous" or "monitoring" because this Monitor runs continuously when the engine is cranking or running.
• This information is a representation of a Drive Cycle, and may vary due to software revisions to the PCM.

COMPONENT MONITOR PRETEST CONDITIONS

• MIL is off.
• Battery voltage between 11-16v.
• Key on or engine running at idle or cruise speed.

TEST PROCEDURE

1. Connect the Scan Tool to the data link connector (DLC).
2. Start the engine and allow it to run at idle speed for 1-2 minutes.
3. Accelerate at part-throttle to Cruise speed and maintain that speed for several minutes. Bring the vehicle to a stop, but do not turn off the ignition key.
4. Check for any diagnostic trouble codes (DTC's) in memory. If any DTC's are set, refer to the appropriate trouble code chart to make the repair. If no DTC's are set, the test is finished. Return to the service bay and turn off the ignition key.

By the ay this is NOT from any FSM, so it is not copywrite infringement.

Click to expand...

Thanks for the info. I still dont get how I can have a injector problem and no driveability problems whatsoever. Ill look into swapping injectors...

Whered you get that info? Much better than the FSM that I have

summitlt said:

Thanks for the info. I still dont get how I can have a injector problem and no driveability problems whatsoever. Ill look into swapping injectors...

Whered you get that info? Much better than the FSM that I have

Click to expand...

Top secret.:cheers: I would sooner believe you have a PCM issue, since there are no drivability issues.