With PFI

Code 22 Chart:

Code 22 Wiring Diagram:

CIRCUIT DESCRIPTION:

The Throttle Position Sensor (TPS) provides a voltage signal that changes relative to the throttle blade. Signal voltage will vary from less than 1.0 volt at idle to about 4.5 volts at Wide Open Throttle (WOT). 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: Because of all the possible color code combinations used on electrical wiring diagrams, always refer to ECM CONNECTOR IDENTIFICATION under ELECTRICAL AND ELECTRONIC WIRING DIAGRAMS for correct color code identification of circuit.


TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Code 22 will set if:

^ Engine is running.
^ TPS voltage is less than 0.2 volt for 4 seconds.

2. Simulates code 21 (high voltage). If the ECM recognizes the high signal voltage the ECM and wiring are OK.

3. With closed throttle, ignition "ON" or at idle, voltage at "YF13" should be 0.36-0.44 volt. If not replace the TPS. Refer to COMPONENT REPAIR AND REPLACEMENT PROCEDURES.

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 the throttle is moved toward 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.

^ Poor Connection or Damaged Harness. Inspect ECM harness connectors for backed out terminal "YF13", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.


^ Intermittant Test. If connection and harness check OK, monitor TPS voltage display while moving related connectors and wiring harness. If the failure is induced, the display will change, this may help to isolate the location of the malfunction.

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