The Idle Learn procedure may be required when:
1.) The PCM loses power or ground (battery or PCM disconnected)
2.) Service programming is performed on a replacement PCM
3.) Service programming is performed on an existing PCM
4.) The IAC motor is replaced
If a rough idle is present after vehicle service has been performed, the Idle Learn procedure should be performed.
The Idle Learn procedure differs for vehicles with an automatic or manual transmission. In addition, several steps were eliminated beginning with 1999 model year vehicles. These steps are indicated below with an asterick (*).
Automatic Transmission
1.) Turn ignition "OFF"
2.) Restore PCM battery feed
3.) Turn "OFF" all A/C controls *
4.) Set parking brake and block wheels
5.) Start engine and warmup to a minimum of 176F degrees (80C)
6.) Shift transmission selector to "DRIVE"
7.) Allow engine to idle for 5 minutes
8.) Turn on A/C controls *
9.) Allow engine to idle for another 5 minutes *
10.) Shift transmission selector to "PARK"
11.) Allow engine to idle for another 5 minutes
12.) Turn off A/C controls *
13.) Allow engine to idle again for 5 minutes
14.) Turn engine "OFF" for 30 seconds
Manual Transmission
1.) Turn ignition "OFF"
2.) Restore PCM battery feed
3.) Turn off all A/C controls
4.) Set parking brake and block drive wheels
5.) Place transmission in "NEUTRAL"
6.) Start engine and warm-up to a minimum of 176F degrees (80C)
7.) Turn on A/C controls *
8.) Allow engine to idle for 5 minutes *
9.) Turn off A/C controls *
10.) Allow engine to idle again for 5 minutes
11.) Turn engine "OFF" for 30 seconds
Functional Check
After performing the Idle Learn procedure and/or the CKP Variation Learn procedure, perform a functional check of the PCM.
1.) Use a Tech 2 to "Capture Info"
2.) Clear Diagnostic Trouble Codes (DTCs), if any are stored
3.) Perform the On-Board Diagnostic System Check
4.) Start engine and let it idle for one (1) minute
5.) Use a scan tool to check for DTCs
6.) Service any DTCs according to service information procedures