I have checked, but...
Senior Member
Joined: Dec 2000
Posts: 298
Likes: 0
From: Ivanhoe, Tx , America
Uhhhhhhhh the only problem with this is that it drains all codes. you will need to restart your truck a number of times, I think the threshold is 50 times before all codes are reset or something
Member
Joined: Jul 2001
Posts: 70
Likes: 0
From: Iowa
Ok ... I think I have answered my own question. Here is the info I found in varous places on the net and now verified it in the shop manual. Also note the reference to the Transmission shifting issue. I thought my Tray was broke after I reset the PCM while testing. but it returned to normal.
All OBD II scan tools display the On-Board System Readiness (OSR) Test. The OSR will display the supported monitors on the vehicle and the status of all monitors (complete or not complete) at that time. Fuel, misfire and comprehensive component monitors run continuously and will always display "YES" status. Only a PCM reset or a keep alive RAM reset will cause the non-continuous monitors to reinitialize to "NO" status.
“Resetting Keep Alive RAM will return PCM memory to its default setting. Adaptive learning contents such as idle and fuel trim are included. A PCM Reset (described above) is also part of a KAM Reset.
After Keep Alive RAM has been reset, the vehicle may exhibit certain driveability concerns. It will be necessary to drive the vehicle to allow the PCM to relearn values for optimum driveability and performance. The customer needs to be notified that they may experience slightly different upshifts either soft or firm and that this condition is temporary and will eventually return to normal operating condition.
This function may not be supported by all scan tools. Refer to scan tool manufacturer's instruction manual.
If an error message is received or the scan tool does not support this function, disconnecting the battery ground cable for a minimum of 5 minutes may be used as an alternative procedure. “
The following events occur when a PCM reset is performed:
Clears the number of Diagnostic Trouble Codes (DTCs).
1 Clears the DTCs.
2 Clears the freeze frame data.
3 Clears diagnostic monitoring test results.
4 Resets status of the OBD II system monitors.
5 Sets DTC P1000 code.
Drive Cycle Description:
Drive Cycle Recommendations
1. Most OBDII monitors will complete more readily using a "steady foot" driving style during cruise or acceleration modes. Operating the throttle in a "smooth" fashion will minimize the time required for monitor completion.
2. Fuel tank level should be between 1/2 and 3/4 fill with 3/4 fill being the most desirable.
3. The Evaporative Monitor can only operate during the first 30 minutes of engine operation. When executing the procedure for this monitor, stay in part throttle mode and drive in a smooth fashion to minimize "fuel slosh".
Drive Cycle steps that MUST be completed.
HEGO - Cruise at 40 MPH for at least 5 minutes. - Executes the HEGO monitor.
EVAP - Cruise at 45 to 65 MPH for 10 minutes (avoid sharp turns ) - Executes the EVAP monitor (If IAT is within 40 to 100F).
Catalyst - Drive in stop-and-go traffic conditions. Include five different constant cruise speeds, ranging from 25 to 45 MPH over a 10-minute period. - Executes the Catalyst Monitor.
EGR - From a stop, accelerate to 45 MPH at 1/2 to 3/4 throttle. Repeat 3 times. - Executes the EGR Monitor.
SEC AIR/CCM - Bring the vehicle to a stop. Idle Engine with transmission in drive for 2 minutes. - Executes the ISC portion of the CCM.
CCM - From a stop and in overdrive, moderately accelerate to 50 MPH and cruise for at least 15 seconds. Stop vehicle and repeat without overdrive to 40 MPH cruising for at least 30 seconds. While 40 MPH, activate overdrive and accelerate to 50 MPH and cruise for at least 15 seconds. Stop for at least 20 seconds and repeat step five times. - Executes the transmission portion of CCM
Misfire & Fuel Monitors - From a stop, accelerate to 65 MPH. Decelerate at closed throttle 40 MPH (no brakes). Repeat this 3 times. - Allows learning for the misfire monitor.
This should complete the On-Board System Readiness (OSR) Test and reset the DTC P1000 code.
If not...
EVAP Monitor Bypass - Park vehicle for a minimum of 8 hours. Repeat steps above - Allow the "bypass" counter to increment by two
( Sorry for the long post but I thought this would be usefull)
David
All OBD II scan tools display the On-Board System Readiness (OSR) Test. The OSR will display the supported monitors on the vehicle and the status of all monitors (complete or not complete) at that time. Fuel, misfire and comprehensive component monitors run continuously and will always display "YES" status. Only a PCM reset or a keep alive RAM reset will cause the non-continuous monitors to reinitialize to "NO" status.
“Resetting Keep Alive RAM will return PCM memory to its default setting. Adaptive learning contents such as idle and fuel trim are included. A PCM Reset (described above) is also part of a KAM Reset.
After Keep Alive RAM has been reset, the vehicle may exhibit certain driveability concerns. It will be necessary to drive the vehicle to allow the PCM to relearn values for optimum driveability and performance. The customer needs to be notified that they may experience slightly different upshifts either soft or firm and that this condition is temporary and will eventually return to normal operating condition.
This function may not be supported by all scan tools. Refer to scan tool manufacturer's instruction manual.
If an error message is received or the scan tool does not support this function, disconnecting the battery ground cable for a minimum of 5 minutes may be used as an alternative procedure. “
The following events occur when a PCM reset is performed:
Clears the number of Diagnostic Trouble Codes (DTCs).
1 Clears the DTCs.
2 Clears the freeze frame data.
3 Clears diagnostic monitoring test results.
4 Resets status of the OBD II system monitors.
5 Sets DTC P1000 code.
Drive Cycle Description:
Drive Cycle Recommendations
1. Most OBDII monitors will complete more readily using a "steady foot" driving style during cruise or acceleration modes. Operating the throttle in a "smooth" fashion will minimize the time required for monitor completion.
2. Fuel tank level should be between 1/2 and 3/4 fill with 3/4 fill being the most desirable.
3. The Evaporative Monitor can only operate during the first 30 minutes of engine operation. When executing the procedure for this monitor, stay in part throttle mode and drive in a smooth fashion to minimize "fuel slosh".
Drive Cycle steps that MUST be completed.
HEGO - Cruise at 40 MPH for at least 5 minutes. - Executes the HEGO monitor.
EVAP - Cruise at 45 to 65 MPH for 10 minutes (avoid sharp turns ) - Executes the EVAP monitor (If IAT is within 40 to 100F).
Catalyst - Drive in stop-and-go traffic conditions. Include five different constant cruise speeds, ranging from 25 to 45 MPH over a 10-minute period. - Executes the Catalyst Monitor.
EGR - From a stop, accelerate to 45 MPH at 1/2 to 3/4 throttle. Repeat 3 times. - Executes the EGR Monitor.
SEC AIR/CCM - Bring the vehicle to a stop. Idle Engine with transmission in drive for 2 minutes. - Executes the ISC portion of the CCM.
CCM - From a stop and in overdrive, moderately accelerate to 50 MPH and cruise for at least 15 seconds. Stop vehicle and repeat without overdrive to 40 MPH cruising for at least 30 seconds. While 40 MPH, activate overdrive and accelerate to 50 MPH and cruise for at least 15 seconds. Stop for at least 20 seconds and repeat step five times. - Executes the transmission portion of CCM
Misfire & Fuel Monitors - From a stop, accelerate to 65 MPH. Decelerate at closed throttle 40 MPH (no brakes). Repeat this 3 times. - Allows learning for the misfire monitor.
This should complete the On-Board System Readiness (OSR) Test and reset the DTC P1000 code.
If not...
EVAP Monitor Bypass - Park vehicle for a minimum of 8 hours. Repeat steps above - Allow the "bypass" counter to increment by two
( Sorry for the long post but I thought this would be usefull)
David
Last edited by David10n; Aug 18, 2001 at 11:00 AM.
