DTC Troubleshooting: P0502 (17-8)

DTC P0502: VSS Circuit Malfunction Test-drive the vehicle with the speed more than 20 km/h (12.5 mph). Check the vehicle speed with the HDS. Is the correct speed indicated?
YES | - | Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the VSS and the ECM.■
NO | - | Go to Step 3 .
Turn the ignition switch OFF. Disconnect the VSS 3P connector. Turn the ignition switch ON (II). Measure voltage between VSS 3P connector terminal No. 1 and body ground. Is there about 5 V?
YES | - | Go to Step 11 .
NO | - | Go to Step 7 .
Turn the ignition switch OFF, and wait 30 seconds. Disconnect ECM connector No. 1 (96P). |

Connect VSS 3P connector terminal No. 1 to body ground with a jumper wire. |

Check for continuity between ECM connector No. 1 terminal No. 30 and body ground. Is there continuity?
YES | - | Go to Step 29 .
NO | - | Repair open in the wire between the VSS and ECM connector No. 1 terminal No. 30, then go to Step 24 .

Measure voltage between VSS 3P connector terminal No. 2 and body ground. Is there about 5 V?
YES | - | Go to Step 17 .
NO | - | Go to Step 12 .
Turn the ignition switch OFF, and wait 30 seconds. Disconnect ECM connector No. 1 (96P). |

Check for continuity between VSS 3P connector terminal No. 2 and body ground. Is there continuity?
YES | - | Repair short in the wire between the VSS and ECM connector No. 1 terminal No. 84, then go to Step 24 .
NO | - | Go to Step 15 .

Connect VSS 3P connector terminal No. 2 to body ground with a jumper wire. |

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 VSS and ECM connector No. 1 terminal No. 84, then go to Step 24 .

Measure voltage between VSS 3P connector terminals No. 1 and No. 3. Is there about 5 V?
YES | - | Go to Step 22 .
NO | - | Go to Step 18 .
Turn the ignition switch OFF, and wait 30 seconds. Disconnect ECM connector No. 1 (96P). |

Connect VSS 3P connector terminal No. 3 to body ground with a jumper wire. |

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 VSS and ECM connector No. 1 terminal No. 54, then go to Step 24 .
Turn the ignition switch OFF. Replace the VSS. Reconnect all connectors. Turn the ignition switch ON (II). Reset the ECM with the HDS. Test-drive under these conditions: Transmission in 3rd gear Engine speed at 2,000 rpm (min −1 ) or more Check for Temporary DTCs or DTCs with the HDS. Are any Temporary DTCs or DTCs indicated?
YES | - | If DTC P0502 is indicated, check for poor connections or loose terminals at the VSS and the ECM, then go to Step 1 . If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO | - | Troubleshooting is complete.■
Update the ECM if it does not have the latest software, or substitute a known-good ECM. Test-drive under these conditions: Transmission in 3rd gear Engine speed at 2,000 rpm (min −1 ) or more Check for Temporary DTCs or DTCs with the HDS. Are any Temporary DTCs or DTCs indicated?
YES | - | If DTC P0502 is indicated, check for poor connections or loose terminals at the VSS and the ECM, then go to Step 1 . If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO | - | If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. ■