Diagnostic Aids

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used to diagnose the following:

Speed Control Indicator (SCI).
Speed Control Overdrive Cut (SCODC).
Faulty TCM.

Fig 1: Speed Control Circuits/Control Module Harness Connector

CIRCUIT PIN IDENTIFICATION (TEST SC)

Circuit	Breakout Box Pin No.	TCM Pin	Wire Color
SCI	29	37	Yellow/Red
SCODC	19	40	Light Green/Red

Step 1) Check Signal Between Speed Control Module And TCM Turn ignition off. Connect NGS to diagnostic connector. Start engine. Access SC STS and SCODC PIDs. Drive the vehicle. Press the cruise control ON button. Read the SC STS signal and the SCODC signal when setting SC ON and when applying ACCEL.

CRUISE CONTROL SWITCH TESTING

Switch Position

NGS Display

SET ON

SC STS ON

SET OFF

SC STS OFF

ACCEL Released

SCODC ⁽¹⁾ OFF

ACCEL Applied

SCODC OFF

⁽¹⁾	SCODC on only when vehicle speed cannot be maintained.

If both signals are as specified, see TESTS W/O CODES article. If both signals are not as specified, go to next step.

Step 2) Check Signal Circuit Turn ignition off. Install 60-pin breakout box (leave TCM disconnected). Disconnect speed control module (located behind right kick panel). Measure resistance between each test pin and each signal wire at speed control module harness connector. Resistance should be less than 5 ohms. Measure resistance between each test pin and ground. Resistance should be greater than 10,000 ohms. Repair any open or shorted circuit. If both resistance measurements are as specified, see the CRUISE CONTROL SYSTEM article.