DTC Troubleshooting: P0502 (17)
DTC P0502:
 Output Shaft (Countershaft) Speed Sensor Circuit Malfunction
NOTE: Before you troubleshoot, record all freeze data and review the general troubleshooting information.
  1. Test-drive the vehicle with the speed more than 20 km/h (12.5 mph).
  1. Check the vehicle speed with the HDS.
Is the correct speed indicated?
YES -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the output shaft (countershaft) speed sensor and the ECM.■
NO -
Go to Step 3 .
  1. Turn the ignition switch OFF.
  1. Disconnect the output shaft (countershaft) speed sensor 3P connector.
  1. Turn the ignition switch ON (II).
  1. Measure voltage between output shaft (countershaft) speed sensor 3P connector terminal No. 1 and body ground.
Is there about 5 V?
YES -
Go to Step 11 .
NO -
Go to Step 7 .
  1. Turn the ignition switch OFF, and wait 2 minutes.
  1. Disconnect ECM connector No. 1 (96P).
  1. Connect output shaft (countershaft) speed sensor 3P connector terminal No. 1 to body ground with a jumper wire.
  1. Check for continuity between ECM connector No. 1 terminal No. 4 and body ground.
Is there continuity?
YES -
Go to Step 29 .
NO -
Repair open in the wire between the output shaft (countershaft) speed sensor and ECM connector No. 1 terminal No. 4, then go to Step 24 .
  1. Measure voltage between output shaft (countershaft) speed sensor 3P connector terminal No. 2 and body ground.
Is there about 5 V?
YES -
Go to Step 17 .
NO -
Go to Step 12 .
  1. Turn the ignition switch OFF, and wait 2 minutes.
  1. Disconnect ECM connector No. 1 (96P).
  1. Check for continuity between output shaft (countershaft) speed sensor 3P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Repair short in the wire between the output shaft (countershaft) speed sensor and ECM connector No. 1 terminal No. 84, then go to Step 24 .
NO -
Go to Step 15 .
  1. Connect output shaft (countershaft) speed sensor 3P connector terminal No. 2 to body ground with a jumper wire.
  1. Check for continuity between ECM connector No. 1 terminal No. 84 and body ground.
Is there continuity?
YES -
Go to Step 29 .
NO -
Repair open in the wire between the output shaft (countershaft) speed sensor and ECM connector No. 1 terminal No. 84, then go to Step 24 .
  1. Measure voltage between output shaft (countershaft) speed sensor 3P connector terminals No. 1 and No. 3.
Is there about 5 V?
YES -
Go to Step 22 .
NO -
Go to Step 18 .
  1. Turn the ignition switch OFF, and wait 2 minutes.
  1. Disconnect ECM connector No. 1 (96P).
  1. Connect output shaft (countershaft) speed sensor 3P connector terminal No. 3 to body ground with a jumper wire.
  1. Check for continuity between ECM connector No. 1 terminal No. 54 and body ground.
Is there continuity?
YES -
Go to Step 29 .
NO -
Repair open in the wire between the output shaft (countershaft) speed sensor and ECM connector No. 1 terminal No. 54, then go to Step 24 .
  1. Turn the ignition switch OFF.
  1. Reconnect all connectors.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. Test-drive under these conditions:
    • Transmission in 3rd gear
    • Engine speed at 2,000 rpm (min −1 ) or more
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0502 indicated?
YES -
Check for poor connections or loose terminals at the output shaft (countershaft) speed sensor and the ECM, then go to Step 1 .
NO -
Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.■
  1. Reconnect all connectors.
  1. Test-drive under these conditions:
    • Transmission in 3rd gear
    • Engine speed at 2,000 rpm (min −1 ) or more
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0502 indicated?
YES -
Check for poor connections or loose terminals at the output shaft (countershaft) speed sensor and the ECM. If the ECM was updated, substitute a known-good ECM, then go to Step 31 . If the ECM was substituted, go to Step 1 .
NO -
If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.■