Dodge Ram Truck 1500-2500-3500. Manual — part 924

P0580-SPEED CONTROL SWITCH 1 CIRCUIT LOW (5.7L) (CONTINUED)

For the Engine circuit diagram (Refer to 9 - ENGINE - SCHEMATICS AND DIAGRAMS).

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
With the ignition key on.

•

Set Condition:
Speed control switch input No.1 is below the minimum acceptable voltage at the PCM. One trip fault.

Possible Causes

(V37) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO THE (V937) S/C SWITCH RETURN

(V37) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO GROUND

CLOCKSPRING

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.

SPEED CONTROL SWITCH VOLTAGE LOW

NOTE: Do not press any of the Speed Control Switch buttons.
Ignition on, engine not running.

With a scan tool, read the Speed Control voltage.

Is the Speed Control voltage below 1.0 volt?

Yes

>> Go To 2

No

>> Refer to the INTERMITTENT CONDITION Diagnostic Procedure.

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

9 - 618

ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L

DR/DH

P0580-SPEED CONTROL SWITCH 1 CIRCUIT LOW (5.7L) (CONTINUED)

2.

SPEED CONTROL SWITCHES

Turn the ignition off.

Remove and disconnect the Speed Control Switches from the steering wheel per Service Information.

Measure the resistance across each Speed Control Switch.

Monitor the ohmmeter while pressing each function button on each switch.

The following resistance specs are taken between terminals (V37) S/C Switch No.1 Signal and (V937) S/C Switch
Return circuits of the Switch when holding the switch button in the following positions.

Not pressing any switch - 20.5 kohms

On/Off - 0.47 kohms

Set - 5.49 kohms

Coast - 2.94 kohms

Cancel - 1.24 kohms

Resume/Accel - 15.4 kohms

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

Yes

>> Go To 3

No

>> Replace the Speed Control Switch that had the incorrect resistance value.

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

3.

SPEED CONTROL ON/OFF SWITCH

Connect the Resume/Accel Switch.

Ignition on, engine not running.

With the scan tool, monitor the Speed Control Switch voltage.

Disconnect the Speed Control On/Off Switch harness connector.

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)

No

>> Go To 4

4.

SPEED CONTROL RESUME/ACCEL SWITCH

With the scan tool, monitor the Speed Control Switch voltage.

Disconnect the Speed Control Resume/Accel Switch harness connector per Service Information.

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)

No

>> Go To 5

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L

9 - 619

P0580-SPEED CONTROL SWITCH 1 CIRCUIT LOW (5.7L) (CONTINUED)

5.

CLOCKSPRING

Turn the ignition off.

Disconnect the clockspring harness connector (instrument panel wiring side) per Service Information.

Ignition on, engine not running.

With the scan tool, read the S/C Switch voltage.

Did the S/C Switch volts change to 5.0 volts?

Yes

>> Replace the Clockspring.

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

No

>> Go To 6

6.

(V37) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO THE (V937) S/C SWITCH RETURN CIRCUIT

Turn the ignition off.

Connect the Clockspring harness connectors per Service Information.

Disconnect the C3 PCM harness connector.

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.
Measure the resistance between the (V937) S/C Switch Return circuit
and the (V37) S/C Switch No.1 Signal circuit at the Speed Control
Switch.

Is the resistance below 5.0 ohms?

Yes

>> Repair the short between the (V37) S/C Switch No.1 Sig-

nal circuit and the (V937) S/C Switch Return circuit.

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

No

>> Go To 7

9 - 620

ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L

DR/DH

P0580-SPEED CONTROL SWITCH 1 CIRCUIT LOW (5.7L) (CONTINUED)

7.

(V37) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (V37) S/C Switch
No.1 Signal circuit in the Switch harness connector.

Is the resistance below 100 ohms?

Yes

>> Repair the short to ground in the (V37) S/C Switch No.1

Signal circuit.

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

No

>> Go To 8

8.

SPEED CONTROL SWITCH VOLTAGE VALUES

Allow the engine to idle.

With a scan tool, monitor the S/C Switch voltage readings.

SWITCH POSITION

SWITCH No.1 VOLTAGE VALUE

SWITCH No.2 VOLATGE 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

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

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L

9 - 621