P1593-SPEED CONTROL SWITCH 1/2 STUCK

For a complete wiring diagram Refer to Section 8W

When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The PCM detects that the (V71) S/C Signal 1 voltage does not match the (V72) S/C Signal 2 voltage.

Possible Causes

INTERMITTENT DTC

(V71) S/C SIGNAL 1 CIRCUIT SHORTED TO VOLTAGE

(V72) S/C SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE

(V71) S/C SIGNAL 1 CIRCUIT SHORTED TO GROUND

(V72) S/C SIGNAL 2 CIRCUIT SHORTED TO GROUND

(V71) S/C SIGNAL 1 CIRCUIT SHORTED TO THE (V937) S/C SWITCH GROUND CIRCUIT

(V72) S/C SIGNAL 2 CIRCUIT SHORTED TO THE (V937) S/C SWITCH GROUND CIRCUIT

(V71) S/C SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE

(V72) S/C SIGNAL 2 CIRCUIT OPEN OR HIGH RESISTANCE

(V937) S/C SWITCH GROUND CIRCUIT OPEN OR HIGH RESISTANCE

CLOCKSPRING

SPEED CONTROL SWITCH

STEERING CONTROL MODULE (SCM)

POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Diagnostic Test

1.DTC IS ACTIVE

NOTE: Refer to the following table when diagnosing speed control switch voltage DTCs.

	Switch 1 Voltage (pin A27)	Switch 2 Voltage (pin A26)
On/Off - Min.	0.5882	3.5294
On/Off - Max.	1.1373	3.9216
Set - Min.	3.1569	1.1765
Set - Max.	3.5686	1.5686
Cancel - Min.	1.5882	2.8431
Cancel - Max.	2.0000	3.2549
Accel - Min.	3.8824	2.0392
Accel - Max.	4.1765	2.4706

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

NOTE: It may be necessary to test drive the vehicle and operate the speed control in order for this DTC to set.

Is the status Active for this DTC?

Yes

Go to2

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

2.SPEED CONTROL SWITCH

NOTE: The voltages should be above 4.8 volts with the Speed Control Switch connector disconnected.

NOTE: The (V71) S/C Signal 1 voltage should be below .2 volts with the jumper wire in place.

NOTE: The (V72) S/C Signal 2 voltage should be below .2 volts with the jumper wire in place.

Are the Speed Control voltages displayed as described?

Yes

Replace the Speed Control Switch in accordance with the Service Information.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Go to3

3.CLOCKSPRING

NOTE: The voltages should be above 4.8 volts with the Steering Control Module (SCM) C5 connector disconnected.

NOTE: The (V71) S/C Signal 1 voltage should be below .2 volts with the jumper wire in place.

NOTE: The (V72) S/C Signal 2 voltage should be below .2 volts with the jumper wire in place.

Are the Speed Control voltages displayed as described?

Yes

Replace the Clockspring in accordance with the Service Information.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Go to4

4.STEERING CONTROL MODULE (SCM)

NOTE: The voltages should be above 4.8 volts with the connector disconnected.

NOTE: The (V71) S/C Signal 1 voltage should be below .2 volts with the jumper wire in place.

NOTE: The (V72) S/C Signal 2 voltage should be below .2 volts with the jumper wire in place.

Are the Speed Control voltages displayed as described?

Yes

Replace the Steering Control Module (SCM) in accordance with the Service Information.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Go to5

5.(V71) S/C SIGNAL 1 CIRCUIT SHORTED TO VOLTAGE

Is there any voltage present?

Yes

Repair the (V71) S/C Signal 1 circuit for a short to voltage.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Go to 6

6.(V72) S/C SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE

Is there any voltage present?

Yes

Repair the (V72) S/C Signal 2 circuit for a short to voltage.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Go to 7

7.(V71) S/C SIGNAL 1 CIRCUIT SHORTED TO GROUND

Is the resistance above 100 ohms?

Yes

Go to 8

Repair the (V71) S/C Signal 1 circuit for a short to ground.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

8.(V72) S/C SIGNAL 2 CIRCUIT SHORTED TO GROUND

Is the resistance above 100 ohms?

Yes

Go to 9

Repair the (V72) S/C Signal 2 circuit for a short to ground.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

9.(V71) S/C SIGNAL 1 CIRCUIT SHORTED TO THE (V937) S/C SWITCH GROUND CIRCUIT

Is the resistance above 100 ohms?

Yes

Go to 10

Repair the (V71) S/C Signal 1 circuit for a short to the Steering Control Module (SCM) circuit.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

10.(V72) S/C SIGNAL 2 CIRCUIT SHORTED TO THE (V937) S/C SWITCH GROUND CIRCUIT

Is the resistance above 100 ohms?

Yes

Go to 11

Repair the (V72) S/C Signal 2 circuit for a short to the (V937) S/C Switch Ground circuit.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

11.(V71) S/C SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE

Is the resistance below 5.0 ohms?

Yes

Go to12

Repair the (V71) S/C Signal 1 circuit for an open circuit or high resistance.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

12.(V72) S/C SIGNAL 2 CIRCUIT OPEN OR HIGH RESISTANCE

Is the resistance below 5.0 ohms?

Yes

Go to13

Repair the (V72) S/C Signal 2 circuit for an open circuit or high resistance.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

13.(V937) S/C SWITCH GROUND CIRCUIT OPEN OR HIGH RESISTANCE

Is the resistance below 5.0 ohms?

Yes

Go to14

Repair the (V937) S/C Switch Ground circuit for an open circuit or high resistance.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

14.POWERTRAIN CONTROL MODULE (PCM)

Were any problems found?

Yes

Repair as necessary.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Replace the Powertrain Control Module (PCM) in accordance with the Service Information.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).