P0585-SPEED CONTROL SWITCH 1/2 CORRELATION

For a complete wiring diagram Refer to Section 8W.

When Monitored:
Ignition on.
Set Condition:
Cruise Switch inputs are not coherent with each other. Example: PCM is reading Switch No.1 as Accel and Switch No.2 as Coast at the same time. One trip fault.

Possible Causes

S/C SWITCH SIGNAL CIRCUITS SHORTED TO BATTERY VOLTAGE

RESISTANCE IN THE S/C SWITCH SIGNAL CIRCUITS

RESISTANCE IN THE (V397/V937) SWITCH RETURN CIRCUIT

S/C SWITCH SIGNAL CIRCUITS SHORTED TO THE (V397/V937) SWITCH RETURN CIRCUIT

(V371/V71) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO THE (V372/V72) S/C SWITCH NO.2 SIGNAL CIRCUIT

S/C SWITCH SIGNAL CIRCUITS SHORTED TO GROUND

STEERING COLUMN CONTROL MODULE

SPEED CONTROL ON/OFF SWITCH

SPEED CONTROL RESUME/ACCEL SWITCH

PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Diagnostic Test

1.ACTIVE DTC

NOTE: This DTC is a two trip fault. If the scan tool indicates a one trip failure, the possible cause may have been the customer pressing both switches simultaneously. Test drive the vehicle and activate the Speed Control system. If the DTC matures to an active fault a repair is necessary.

NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

Is the DTC Active or Pending at this time?

Yes

Go To 2

Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

2.SPEED CONTROL ON/OFF SWITCH

Did the voltage change to above 4.8 volts?

Yes

Replace the Speed Control On/Off Switch.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 3

3.SPEED CONTROL RESUME/ACCEL SWITCH

Did the voltage change to above 4.8 volts?

Yes

Replace the Speed Control Resume/Accel Switch.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 4

4.SPEED CONTROL SWITCHES

Does the function on the Speed Control Switches have the correct resistance value?

Yes

Go To 5

Replace the Speed Control Switch that had the incorrect resistance value.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

5.S/C SWITCH SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE

Is the voltage above 5.0 volts?

Yes

Repair the short to battery voltage in the (V371) or (V372) S/C Switch Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 6

6.STEERING COLUMN CONTROL MODULE

Is the resistance above 5.0 ohms for any one of the measurements?

Yes

Replace the SCCM per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 7
NOTE: Connect the Steering Column Control Module harness connectors per Service Information before continuing.

7.S/C SWITCH SIGNAL CIRCUIT OPEN

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Is the resistance below 5.0 ohms for each measurement?

Yes

Go To 8

Repair the excessive resistance in the (V371/V71) or (V372/V72) S/C Switch Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

8.(V397/V937) SWITCH RETURN CIRCUIT OPEN

NOTE: The measurement must be taken from both Speed Control Switch harness connectors.

Is the resistance below 5.0 ohms for both measurements?

Yes

Go To 9

Repair the excessive resistance in the (V397/V937) Switch Return circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

9.S/C SWITCH SIGNAL CIRCUITS SHORTED TO THE (V397/V937) SWITCH RETURN CIRCUIT

Is the resistance below 5.0 ohms?

Yes

Repair the short between the (V397/V937) Switch Return circuit and the (V371/V71) or (V372/V72) S/C Switch Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 10

10.(V371/V71) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO THE (V372/V72) S/C SWITCH NO.2 SIGNAL CIRCUIT

Is the resistance below 100 ohms for each circuit?

Yes

Repair the short between the (V372/V72) S/C Switch No.2 Signal circuit and the (V371) S/C Switch No.1 Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 11

11.S/C SWITCH SIGNAL CIRCUITS SHORTED TO GROUND

Is the resistance below 100 ohms?

Yes

Repair the short to ground in the (V371/V71) or (V372/V72) S/C Switch Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 12

12.SPEED CONTROL SWITCH VOLTAGE VALUES

SWITCH POSITION	SWITCH No.1 VOLTAGE VALUE	SWITCH No.2 VOLTAGE VALUE
NO SWITCHES PRESSED	4.31 to 4.78 volts	4.31 to 4.78 volts
ON/OFF PRESSED	0.59 to 1.13 volts	3.53 to 3.92 volts
RES/ACCEL PRESSED	3.88 to 4.17 volts	2.04 to 2.47 volts
SET PRESSED	3.16 to 3.56 volts	1.17 to 1.56 volts
COAST PRESSED	2.57 to 2.94 volts	0.77 to 1.09 volts
CANCEL PRESSED	1.59 to 1.99 volts	2.84 to 3.25 volts

Are the voltage readings out of the listed specification and is there less than a 0.2 of a volt difference between the voltmeter switch values and the scan tool switch values?

Yes

Replace the Speed Control Switch.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 13

13.PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Were there any problems found?

Yes

Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)