W T E C I I I E L E C T R O N I C C O N T R O L S T R O U B L E S H O O T I N G M A N U A L
5. If the condition again recurs, connect the diagnostic tool and select the speed signal indicated by
the trouble code. Drive the vehicle and watch the speed reading on the diagnostic tool. If the signal
is erratic, sensor gap, vehicle vibration, an external AC signal source, or intermittent connector
contact may be inducing the erratic signal. Inspect the sensor and its surroundings for irregularities
that would affect sensor gap. Isolate and correct any abnormal vehicle vibrations (particularly
driveline and abnormal engine torsionals. Recheck the sensor wiring for intermittent conditions
(see Appendix A).
6. If the condition persists, replace the ECU. If replacing the ECU corrects the problem, reinstall the
original (bad) ECU to confirm that the problem is in the ECU. If the original ECU now works,
inspect the ECU connectors for any corrosion or damage which may cause an intermittent
condition. If the original problem recurs, reinstall the replacement ECU.
CODE 22 XX SPEED SENSOR/CIRCUITRY FAULT (Figure 55)