DTC Troubleshooting

DIAGNOSIS PROCEDURE

Step	Action	YES	NO
1	Was "Engine and Emission Control System Check" performed?	Go to Step 2.	Go to ENGINE AND EMISSION CONTROL SYSTEM CHECK .
2	Does speedometer indicate vehicle speed?	Go to Step 3.	Go to Step 5.
3	Check vehicle speed signal. Is vehicle speed displayed on scan tool in Step 2) and 4) of "DTC Confirmation Procedure"?	Intermittent trouble or faulty ECM. Check for intermittent referring to INTERMITTENT AND POOR CONNECTION INSPECTION .	Go to Step 4.
4	Check VSS signal circuit Turn ignition switch to OFF position, disconnect connector from VSS. Disconnect connectors from combination meter referring to COMBINATION METER REMOVAL AND INSTALLATION . Turn ON ignition switch, without running engine. Measure voltage from "PPL" wire terminal of VSS connector to engine ground. Is voltage within 4 - 5 V?	Faulty combination meter.	"PPL" wire open or short. Poor connection of ECM connector terminal. If OK, substitute a knowngood ECM and recheck.
5	Check power supply circuit Turn ignition switch to OFF position, disconnect connector from VSS. Check for proper connection to "BLK/RED", "BLK/ORN" and "PPL" wire terminal of VSS connector. If wires are OK, turn ON ignition switch, measure voltage between engine ground and "BLK/RED" wire terminal. Is it voltage 10 - 14 V?	Go to Step 6.	Open wire in "BLK/RED" circuit.
6	Check ground circuit Measure resistance between engine body ground and "BLK/ORN" wire terminal of VSS connector with ignition switch turn OFF. Is resistance below 5 ohm?	Go to Step 7.	Open or high resistance wire in "BLK/ORN" circuit.
7	Check wire circuit Turn ON ignition switch, measure voltage between engine ground and "PPL" wire terminal of VSS connector. Is it voltage 10 - 14 V?	Go to Step 9.	Go to Step 8.
8	Check wire circuit Disconnect connectors from combination meter referring to COMBINATION METER REMOVAL AND INSTALLATION with ignition switch turn OFF. Turn ON ignition switch, measure voltage between engine ground and "PPL" wire terminal of combination meter. Is it voltage 4 - 5 V?	Faulty combination meter.	Go to Step 9.
9	Check wire circuit Turn ON ignition switch, measure voltage between engine ground and "PPL" wire terminal of VSS connector. Is it voltage 4 - 5 V?	Go to Step 13.	Go to Step 10.
10	Check ECM voltage Turn ON ignition switch, measure voltage between vehicle body ground and "G04-35" terminal of ECM connector. Is it voltage 4 - 5 V?	Open wire in "PPL" circuit.	Go to Step 11.
11	Check short circuit Disconnect connectors from ECM with ignition switch turned OFF. Turn ON ignition switch, measure voltage between engine ground and "G04-35" terminal of ECM connector. Is it voltage 0 V?	Go to Step 12.	"PPL" wire shorted to power supply circuit.
12	Check short circuit Measure resistance between engine ground and "G04-35" terminal of ECM connector with ignition switch turned OFF. Is resistance infinity?	Go to Step 13.	"PPL" wire shorted to ground circuit. If wire are OK, substitute a known-good ECM and recheck.
13	Check signal rotor Remove VSS referring to VEHICLE SPEED SENSOR (VSS) REMOVAL AND INSTALLATION . Visually inspect VSS sensor signal rotor for damage. Was any damage found?	Faulty VSS signal rotor.	Go to Step 14.
14	Check VSS Remove metal particles on end face of VSS, if any. Connect connectors to ECM and VSS. Turn ON ignition switch. Check for voltage at "G04-35" terminal of ECM connector by passing magnetic substance (iron) (1) while keeping approximately 1 mm (0.03 in.) gap with respect to end face of VSS. Do voltage vary from low (0 - 1 V) to high (4 - 6) or from high to low?	Substitute a known-good ECM and recheck.	Faulty VSS.