DTC 22

Chart - Code 22 Throttle Position Sensor (Signal Voltage Low):

Wiring Diagram for Throttle Position Sensor:

CODE 22 - THROTTLE POSITION SENSOR (TPS) CIRCUIT (SIGNAL VOLTAGE LOW)


Circuit Description:
The Throttle Position Sensor (TPS) provides a voltage signal that changes relative to throttle blade angle. Signal voltage will vary from about .4 at idle to about 5 volts at wide open throttle. The TPS signal is one of the most important inputs used by the Electronic Control Module (ECM) for fuel control and for most of the ECM control outputs.
NOTE: On 3.OL engines wires A & C are reversed at TPS connector.


Test Description: Numbers below refer to circled numbers on the diagnostic chart.
1. Code 22 will set if engine is running and TPS signal voltage is less than .2 volts for 3 seconds.
2. Simulates Code 21: (high voltage) If ECM recognizes the high signal voltage the ECM and wiring are OK.
3. TPS adjustment
4. Simulates a high signal voltage. Checks CKT 417 for an open.

Diagnostic Aids:

A "Scan" tool reads throttle position in volts. Voltage should increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT). Also some "Scan" tools will read throttle angle 0% = closed throttle 100% = WOT. An open or short to ground in CKT's 416 or 417 will result in a Code 22.



Check For:
Poor Connection, inspect ECM harness connectors for backed out terminals "Cl3" or "D12", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.

Intermittent Test, if connections and harness check out OK, monitor TPS voltage display while moving related connectors and wiring harness. If the failure is induced, the "Coolant Temperature" display will change. This may help to isolate the location of the malfunction

TPS Scaling Observe TPS voltage display while depressing accelerator pedal with engine stopped and ignition "ON". Display should vary from closed throttle TPS voltage when throttle was closed, to over 4.5 volts (4500 mV) when throttle is held at Wide Open Throttle (WOT) position.