E021

Code E021 - Throttle Position Sensor (Signal Voltage High):

Wiring Diagram for Code E021 - Throttle Position Sensor (Signal Voltage High):

CODE E021 - THROTTLE POSITION SENSOR (SIGNAL VOLTAGE HIGH)

Circuit Description:

The Throttle Position Sensor has an output voltage (0-5100 mv) which is monitored by the ECM (terminal C13) to calculate fuel delivery and spark advance (EST) based on the throttle valve angle (driver demand). Voltage to the ECM varies from about 350 to 450 mv at idle, to 4800 to 5100 mv, at wide open throttle.

The TPS signal is one of the most important inputs used by the ECM for fuel control and for most of the ECM controlled outputs.

Code E021 will set if:

a. Engine is running
b. TPS signal voltage is greater than 2500 mv for 5 seconds
c. Code E033 and E034 not present at first start-up when signal voltage is high
d. Air flow in grams/second less than 15
e. All above conditions met continuously for 5 seconds




Test Description: The following numbered steps correspond with the step numbers on the diagnostic chart.

1. Confirm that there is a problem (over 2500 mv display) with ignition "ON".

2. If TPS is disconnected, less than 200 mv displayed indicates an open 452 circuit or a faulty TPS switch.




Diagnostic Aids:

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation.

Check For:

a. Poor Connection or Damaged Harness - Inspect ECM harness connectors for backed out terminals "C13", "C14" or "D12", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.

b. Intermittent Test - If connections and harness checks out ok, monitor ED01 (TPS Voltage) display while moving related connectors and wiring harness. If the failure is induced, the "TPS Voltage" display will abruptly change. This will help to isolate the location of the malfunction.

c. TPS Scaling - Observe TPS Voltage display (ED01) while depressing accelerator pedal with engine stopped and ignition on. Display should vary from closed throttle TPS voltage (350-450mv) when throttle was closed, to over 4500 mv when throttle is held at wide open throttle position.

d. TPS Voltage Test - The following approximate voltages may be observed on a normal TPS circuit:

350 mv To 450 mv - Ignition "ON" or at idle.
4500 mv to 5100 mv - At wide open throttle
40 mv - With TPS disconnected
5000 to 5100 mv - With connector terminals "A" and "B" jumpered.
0 mv - With connector terminals "B" and "C" jumpered.