Circuit Test TP - Throttle Position Sensor

NOTE: To diagnose throttle position on 1.8L M/T, go to CIRCUIT TEST STG. Enter this test only when a Code 12 is displayed during self-test procedures (KOEO or KOER), or when directed here from another CIRCUIT TEST. To prevent replacement of good components, check the following non-EEC components for fault: idle speed or throttle stop adjustments, throttle shaft or linkage, and cruise control linkage.

Fig 1: TP Sensor Circuit & Connector Terminal ID

CIRCUIT PIN IDENTIFICATION

Circuit	Breakout Box Pin No.	ECA Pin	Wire Color
1.8L A/T
IDL	18	1N	Red/White
SIGRTN	46 & 49	2D	Black/White
TP	47	2M	Green/White
VREF	26	2K	Green/Red
2.2L Non-Turbo
A/T
SIGRTN	46 & 49	3D	Green/Yellow
TP	47	2M	Green/Black
VREF	26	2K	Green/Red
M/T
SIGRTN	46 & 49	2D	Green/Yellow
TP	47	2M	Green/Black
VREF	26	2K	Green/Red
2.2L (Turbo)
SIGRTN	46 & 49	3D	Green/Yellow
TP	47	2F	Green/Black
VREF	26	2I	Green/Yellow

1) Checking System Integrity Visually check all wiring, connectors and components for evidence of damage, shorting or looseness. If fault is found, repair as necessary. If no fault is found, go to next step.

2) Checking TP Sensor Voltage Ensure engine is at operating temperature. With ignition off, install breakout box. Turn ignition on. Measure voltage between TP and SIGRTN test pins. Slowly depress accelerator pedal, and compare voltage to specifications shown in VOLTAGE & RESISTANCE SPECIFICATIONS (TP SENSOR). If voltage is within specification, TP circuit is okay; fault is in another circuit or ECA. If voltage is not within specification, go to next step.

3) Checking TP Sensor Signal Return Remove TP sensor connector. Using jumper wire, connect SIGRTN and VREF terminals at connector to TP sensor. Connect voltmeter between TP and SIGRTN terminals at sensor. Turn ignition on. Slowly depress accelerator pedal, and compare voltage to specifications shown in VOLTAGE & RESISTANCE SPECIFICATIONS (TP SENSOR) . If voltage is as specified, repair TP circuit between ECA and TP sensor. If voltage is not as specified, go to next step.

4) Checking SIGRTN/VREF At TP Sensor Remove TP sensor connector. Turn ignition on. Measure voltage between TP wire and SIGRTN wire. If voltage is 4.5-5.5 volts, adjust or replace TP sensor. If voltage is not 4.5-5.5 volts, go to CIRCUIT TEST VREF.

VOLTAGE & RESISTANCE SPECIFICATIONS ⁽¹⁾

Throttle Position

Ohms

Volts

1/8 Open

.998

.989

1/4 Open

1.104

1.60

3/8 Open

1.278

2.37

1/2 Open

1.462

2.74

5/8 Open

1.480

3.15

3/4 Open

1.459

3.43

7/8 Open

1.144

3.60

Full Open

1.072

4.02

⁽¹⁾	Values may vary by 15 percent.