DTC Troubleshooting: P0720 (122)
DTC P0720:
 Output Shaft (Countershaft) Speed Sensor Circuit Malfunction
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
  1. Start the engine. Hold the engine speed at 3,000 rpm (min −1 ) without load (in neutral) until the radiator fan comes on, then let it idle.
  1. Test-drive several minutes.
  1. Check the C SHAFT SPD in the DATA LIST with the HDS.
Is any vehicle 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/PCM.■
NO -
Go to Step 4 .
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect the output shaft (countershaft) speed sensor 3P connector.
  1. Turn the ignition switch to ON (II).
  1. Measure the voltage between output shaft (countershaft) speed sensor 3P connector terminal No. 1 and body ground.
Is there about 5 V?
YES -
Go to Step 8 .
NO -
Repair open in the wire between the ECM/PCM (C13) and the output shaft (countershaft) speed sensor, then go to Step 18 .