DTC Test 13: Actuator Position Sensor Circuit

WARNING: This page is about a different car, the 1997 Lexus SC 300. However, it is still accessible from the selected car via links, so may be relevant.

Remove cruise control ECU with electrical connectors still attached. Turn ignition on. Measure voltage between specified terminals of cruise control ECU connector while moving control arm by hand. See POSITION SENSOR VOLTAGE table. See Fig 1.
If voltage is not as specified, go to next step. If voltage is as specified:
- CODE - Check for intermittent condition (poor connections, etc.). If connections are okay, replace cruise control ECU.
- NO CODE - Perform next procedure listed in DIAGNOSIS BY SYMPTOM table in TROUBLE SHOOTING.
Disconnect electrical connector from actuator motor. Measure resistance between specified terminals of actuator motor connector. See POSITION SENSOR RESISTANCE table. See Figure. If resistance is not as specified, replace actuator.
If resistance is as specified, check for faulty circuit between cruise control ECU and actuator. If circuit is not okay, check wiring harness and connectors for loose connections. Repair as necessary. If circuit is okay, replace cruise control ECU.

POSITION SENSOR VOLTAGE

Terminals No. ⁽¹⁾

⁽²⁾ Volts

25 & 26

Full Deceleration

0.6-1.6

Full Acceleration

3.4-5.1

⁽¹⁾	See Figure.

⁽²⁾	While slowly moving control arm back and forth between acceleration position and deceleration position, voltage should increase and decrease gradually, without interruption.

POSITION SENSOR RESISTANCE

Terminals No. ⁽¹⁾

Ohms

1 & 3

1600-2400

2 & 3 ⁽²⁾

Full Deceleration

200-800

Full Acceleration

1200-2400

⁽¹⁾	See Figure.

⁽²⁾	Measure resistance while slowly moving control arm back and forth between acceleration position and deceleration position. Resistance should increase and decrease gradually, without interruption.

Fig 1: Identifying Cruise Control ECU Connector Terminals