Throttle Position Sensor (TPS)

Unplug TPS harness at sensor. Connect ohmmeter between Blue/Red or Yellow/Blue and Black/White wire terminals of sensor.
Resistance should vary smoothly as throttle is moved from idle to wide open throttle. Resistance reading should not drop or climb suddenly as continuity is checked. Replace sensor if defective.
To check sensor operating voltage, connect TPS harness. Sensor operating voltage may be monitored at ECM with ignition on. ECM is located behind left side of instrument panel.
NOTE: DO NOT confuse transaxle Electronic Control Unit (ECU), located on left side of instrument panel, with ECM located behind air duct. ECM contains a 24-pin and 32-pin connector. Transaxle ECU contains a 16-pin and 20-pin connector.
On all models, turn ignition on. DO NOT start engine. Using digital voltmeter, backprobe ECM connector terminals to check if 5-volt TPS reference signal is present. Reference signal should be present at ECM terminal C14 (Blue/Orange wire).
If 5-volt reference signal is not present, check for short to ground in 5-volt reference line from ECM to TPS. If no short is present, ECM is defective.
If 5-volt reference signal is present, test TPS input signal at appropriate ECM terminal. Connect negative voltmeter probe to ground. Backprobe ECM terminal with positive voltmeter probe at ECM wire terminal C13 (Yellow/Blue wire).
With engine running, voltage should read approximately .5 volt at idle and increase to approximately 5 volts at wide open throttle. If voltage reading is incorrect, check wiring to TPS. If wiring is okay, replace TPS.

NOTE: Code 21A or 21B may set if a malfunction in TPS exists. For additional TPS testing procedures, see appropriate TESTS W/CODES article in the ENGINE PERFORMANCE Section.