When troubleshooting a misfire problem, you need to make sure that you completely reset the PCM or lingering artifacts in memory may corrupt sensor input interpretation.
Curated from JeepForum.com
Curated from WranglerForum.com
Curated from fs1inc.com (Flagship 1)
PCM : (Powertrain Control Module, akaECM)
TCM : (Transmission Control Module)
Adaptive Numerator : (Logic and storagein PCM that dynamically tunes engine/trans performance and is theprimary means of detecting a misfire)
This very simple procedure will erase the "Adaptive Memory" stored inside the PCM and allow a new Adaptive Memory to be developed. After performing this procedure the 1996-2001 PCM will re-learn and storeinto 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 adaptive mode.
1. Make sure ALL electronics are turned off. Everything.
2. Disconnect the NEGATIVE batteryterminal clamp
3. Disconnect the POSITIVE batteryTerminal clamp
4. Touch and hold the two clamps together while BOTH CLAMPS ARE DISCONNECTED FROM THE BATTERY for at least 15 minutes. This discharges the PCM capacitors and erases Adaptive Numerator memory. ***NOTE***, if you have already done this 15 minute touch-together step and (for whatever reason) you think you need to do it again, do the touch-together over night (12-24 hours). It seems that might make a difference for some god-knows-why reason. There may be some sort of weird EPROM chip in the sealed PCM case that needs extra time to deplete static memory.
5. Turn Headlight "On" and "Off"several times to flush headlight capacitor charge from circuitry
6. Turn the Ignition Switch “On” so that the instrument panel lights up but do not start the engine. Turn off anything that shows life. Various vehicle electrical components also have capacitors. Zero energy in the circuits is the goal. , Turn the ignition to “Off” again. Repeat to confirm.
7. Reconnect the POSITIVE battery terminal clamp (reverse order)
8. Reconnect the NEGATIVE battery terminalclamp
9. Turn Ignition Switch to the "On"position but do not start the engine, then turn it “Off” again. This will reenergize auxiliary capacitors.
10. Turn the headlights "On" and then "Off" again to reenergize those capacitors.
11. Additional TCM memory reset procedure: With the ignition key still in the "On" position with engine OFF, slowly press the accelerator pedal to the floor and slowly release it, twice. Then slowly press the accelerator to the floor a third time, hold it there for 15 seconds, then slowly release again. Turn the ignition key to the "Off" position, wait for 120 seconds, then start the vehicle.
At this point, the PCM Adaptive memory has been completely erased. When you start the engine it will reinitialize with factory pre-programmed ROM tables, and when the engine gets to closed loop state the PCM will reactivate the Adaptive Numerator processes and start to collect data for the Adaptive Memory.
How to expedite the PCM relearning process. Do all of this without triggering a misfire MIL and you should be good to go.
Baseline Monitor Drive Trace
Pre-Conditioning Requirements
- MIL must be off
- Cold start (meaning that you can touch the block without burning yourself)
Driving Procedure
1) Warm engine up for 5 minutes (or until you reach closed loop state)
2) Find a length of road where you can drive (with steady throttle) at 40-60 mph for 8 minutes
3) Stop and idle for 3 minutes
4) Drive (with steady throttle) at a speed >20 mph for 2 minutes
5) Stop, turn key to "Off", leave off for 10 minutes (runs O2 sensor heater monitor)
Catalyst Monitor Drive Trace
Pre-Conditioning Requirements
- MIL must be off
- No DTCs present
- Fuel level between 15-85% full
- ECT (engine coolant temp) above 70º F
- Engine must have run at least 90 seconds
- Engine between 1350-1900 rpm
Driving Procedure
1) Idle vehicle for 5 minutes (or until you reach closed loop state)
2) Drive at a steady speed between 30-45 mph for 2 minutes
EGR System Monitor Drive Trace - Vacuum
Pre-Conditioning Requirements
- MIL must be off
Driving Procedure
1) Idle vehicle 5 minutes (or until you reach closed loop state)
2) Drive with a steady vehicle speed between 40-60 mph for 8 minutes
EGR System Monitor Drive Trace -Electronic
Pre-Conditioning Requirements
- MIL must be off
- MAP must be between 0-60 KPa
- Engine speed between 500-850 rpm
- ECT (engine coolant temp) is above 180º F (90º C)
- No misfire stored or pending
- Make sure the heater and/or AC is "Off", and do not touch the steering wheel while idling
Driving Procedure
1) Idle vehicle in "Park" for 5 minutes (or until you reach closed loop state)
2) Drive with a steady vehicle speed between 40-60 mph for 2 minutes
3) Idle vehicle for 3 minutes
Note: Any conditions causing un-stable idle will prevent this monitor from running correctly
Evaporative System Monitor Drive Trace
Pre-Conditioning Requirements
- MIL must be off
- No Evaporative diagnostic trouble codes present
- Fuel level is between 50-100% full
Driving Procedure
1) Idle vehicle for 5 minutes (or until you reach closed loop state)
2) Drive with a steady vehicle speed between 30 and 45 mph for 2 minutes
Leak Detection Pump Drive Trace
Pre-Conditioning Requirements
- MIL must be off
- No Evaporative DTCs present
- Fuel level is between 30-85% full
Driving Procedure
1) Cold start (engine touchable without burning hand) and idle in "Park" for 4 minutes
2) Drive in-town (stop and go) for 5 minutes, using smooth accelerations and decelerations
3) Stop and idle vehicle for 4 minutes
O2 Sensor Monitor Drive Trace
Pre-Conditioning Requirements
- MIL must be off
Driving Procedure
1) Idle vehicle for 5 minutes (or until you reach closed loop state)
2) Drive with a steady vehicle speed >25 mph for 2 minutes
3) Stop and idle for 30 seconds
4) Smoothly accelerate to a speed between 30-40 mph
5) Repeat steps #3 & #4 five times
O2 Sensor Heater Monitor Drive Trace
Pre-Conditioning Requirements
- MIL must be off
Driving Procedure
1) Idle vehicle for 5 minutes (or until you reach closed loop state)
2) Shut engine off and leave vehicle off for 10 minutes
Curated from JeepForum.com
Curated from WranglerForum.com
Curated from fs1inc.com (Flagship 1)
PCM : (Powertrain Control Module, akaECM)
TCM : (Transmission Control Module)
Adaptive Numerator : (Logic and storagein PCM that dynamically tunes engine/trans performance and is theprimary means of detecting a misfire)
This very simple procedure will erase the "Adaptive Memory" stored inside the PCM and allow a new Adaptive Memory to be developed. After performing this procedure the 1996-2001 PCM will re-learn and storeinto 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 adaptive mode.
1. Make sure ALL electronics are turned off. Everything.
2. Disconnect the NEGATIVE batteryterminal clamp
3. Disconnect the POSITIVE batteryTerminal clamp
4. Touch and hold the two clamps together while BOTH CLAMPS ARE DISCONNECTED FROM THE BATTERY for at least 15 minutes. This discharges the PCM capacitors and erases Adaptive Numerator memory. ***NOTE***, if you have already done this 15 minute touch-together step and (for whatever reason) you think you need to do it again, do the touch-together over night (12-24 hours). It seems that might make a difference for some god-knows-why reason. There may be some sort of weird EPROM chip in the sealed PCM case that needs extra time to deplete static memory.
5. Turn Headlight "On" and "Off"several times to flush headlight capacitor charge from circuitry
6. Turn the Ignition Switch “On” so that the instrument panel lights up but do not start the engine. Turn off anything that shows life. Various vehicle electrical components also have capacitors. Zero energy in the circuits is the goal. , Turn the ignition to “Off” again. Repeat to confirm.
7. Reconnect the POSITIVE battery terminal clamp (reverse order)
8. Reconnect the NEGATIVE battery terminalclamp
9. Turn Ignition Switch to the "On"position but do not start the engine, then turn it “Off” again. This will reenergize auxiliary capacitors.
10. Turn the headlights "On" and then "Off" again to reenergize those capacitors.
11. Additional TCM memory reset procedure: With the ignition key still in the "On" position with engine OFF, slowly press the accelerator pedal to the floor and slowly release it, twice. Then slowly press the accelerator to the floor a third time, hold it there for 15 seconds, then slowly release again. Turn the ignition key to the "Off" position, wait for 120 seconds, then start the vehicle.
At this point, the PCM Adaptive memory has been completely erased. When you start the engine it will reinitialize with factory pre-programmed ROM tables, and when the engine gets to closed loop state the PCM will reactivate the Adaptive Numerator processes and start to collect data for the Adaptive Memory.
How to expedite the PCM relearning process. Do all of this without triggering a misfire MIL and you should be good to go.
Baseline Monitor Drive Trace
Pre-Conditioning Requirements
- MIL must be off
- Cold start (meaning that you can touch the block without burning yourself)
Driving Procedure
1) Warm engine up for 5 minutes (or until you reach closed loop state)
2) Find a length of road where you can drive (with steady throttle) at 40-60 mph for 8 minutes
3) Stop and idle for 3 minutes
4) Drive (with steady throttle) at a speed >20 mph for 2 minutes
5) Stop, turn key to "Off", leave off for 10 minutes (runs O2 sensor heater monitor)
Catalyst Monitor Drive Trace
Pre-Conditioning Requirements
- MIL must be off
- No DTCs present
- Fuel level between 15-85% full
- ECT (engine coolant temp) above 70º F
- Engine must have run at least 90 seconds
- Engine between 1350-1900 rpm
Driving Procedure
1) Idle vehicle for 5 minutes (or until you reach closed loop state)
2) Drive at a steady speed between 30-45 mph for 2 minutes
EGR System Monitor Drive Trace - Vacuum
Pre-Conditioning Requirements
- MIL must be off
Driving Procedure
1) Idle vehicle 5 minutes (or until you reach closed loop state)
2) Drive with a steady vehicle speed between 40-60 mph for 8 minutes
EGR System Monitor Drive Trace -Electronic
Pre-Conditioning Requirements
- MIL must be off
- MAP must be between 0-60 KPa
- Engine speed between 500-850 rpm
- ECT (engine coolant temp) is above 180º F (90º C)
- No misfire stored or pending
- Make sure the heater and/or AC is "Off", and do not touch the steering wheel while idling
Driving Procedure
1) Idle vehicle in "Park" for 5 minutes (or until you reach closed loop state)
2) Drive with a steady vehicle speed between 40-60 mph for 2 minutes
3) Idle vehicle for 3 minutes
Note: Any conditions causing un-stable idle will prevent this monitor from running correctly
Evaporative System Monitor Drive Trace
Pre-Conditioning Requirements
- MIL must be off
- No Evaporative diagnostic trouble codes present
- Fuel level is between 50-100% full
Driving Procedure
1) Idle vehicle for 5 minutes (or until you reach closed loop state)
2) Drive with a steady vehicle speed between 30 and 45 mph for 2 minutes
Leak Detection Pump Drive Trace
Pre-Conditioning Requirements
- MIL must be off
- No Evaporative DTCs present
- Fuel level is between 30-85% full
Driving Procedure
1) Cold start (engine touchable without burning hand) and idle in "Park" for 4 minutes
2) Drive in-town (stop and go) for 5 minutes, using smooth accelerations and decelerations
3) Stop and idle vehicle for 4 minutes
O2 Sensor Monitor Drive Trace
Pre-Conditioning Requirements
- MIL must be off
Driving Procedure
1) Idle vehicle for 5 minutes (or until you reach closed loop state)
2) Drive with a steady vehicle speed >25 mph for 2 minutes
3) Stop and idle for 30 seconds
4) Smoothly accelerate to a speed between 30-40 mph
5) Repeat steps #3 & #4 five times
O2 Sensor Heater Monitor Drive Trace
Pre-Conditioning Requirements
- MIL must be off
Driving Procedure
1) Idle vehicle for 5 minutes (or until you reach closed loop state)
2) Shut engine off and leave vehicle off for 10 minutes
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