2000 & LATER ISUZU NPR; CHEVY FORWARD; GMC TILTMASTER TPS RELEARN PROCEDURE COMPLAINT: CAUSE: CORRECTION: The transmission is stacked shifting and has no kickdown. Code 21, for a TPS circuit fault is stored. All TPS circuits check within specs and adjusting the TPS does not allow code 21 to be cleared or the complaints to disappear. These vehicles require a TPS relearn procedure whenever the engine, injection pump, accelerator cable, throttle linkage, throttle position sensor or kickdown switch are replaced. Failure to do so will result in the above complaints. The following procedure is used for the TPS voltage relearn: Clearing TCM Memory of Current TPS Voltage 1. Turn starter switch to the “ON” position. 2. Turn the overdrive switch to the “ON” position. 3. Place the selector lever in the manual “1” range. 4. Depress the accelerator pedal fully, listen for the kickdown switch click. 5. Depress the brake pedal, (brake switch “ON”). If the memory is successfully cleared, the “Check Trans” lamp flashes 5 times. Preparation For Relearn 1. Turn the starter switch to the “ON” position. 2. Connect terminals 4 and 11 of the Data Link Connector as seen in Figure 1, the    “Check Trans” lamp begins flashing at 0.4 second intervals. 3. Place selector lever in the “P” range. WOT Voltage Relearn 1. Depress accelerator pedal fully. 2. With the accelerator pedal still at WOT, depress brake pedal for more than 3     seconds. 3. The “Check Trans” lamp should now flash intermittently, then illuminate for 3     seconds, then flash 6 times slowly, then flash intermittently again. At this time,     release the brake and accelerator pedals. The “Check Trans” lamp should illuminate      for 3 seconds. If it does not, do the “Clear Memory” procedure above and repeat the     WOT relearn procedure beginning with item 2 under “Preparation”. Idle Position Voltage Relearn 1. Start the engine. 2. Depress the accelerator pedal slowly 3 times. 3. Remove the jumper wire from the Data Link Connector. At this time the “Check    Trans” lamp should stop flashing. If it does  not, or there is mis-operation, begin the    procedure again from the start. Copyright © 2004 ATSG " 2 0 0 5 "  S E M I N A R  I N F O R M A T I O N Automatic Transmission Service Group SLIDE 88