Dodge Ram Truck 1500-2500-3500. Manual — part 996

P2138-ACCELERATOR PEDAL POSITION SENSOR 1/2 CORRELATION (CONTINUED)

8.

CHECKING APPS NO.1 AND NO.2 WITH A LAB SCOPE

Ignition on, engine not running.

Set up a lab scope in a way that you can view two graphs simultaneously.

Backprobe (K23) APP Sensor No.1 Signal circuit using Channel 1 at the APP Sensor harness connector.

Backprobe (K29) APP Sensor No.2 Signal circuit using Channel 2 at the APP Sensor harness connector.

Slowly press and release the Accelerator Pedal while monitoring the lab scope screen.

Does the scope pattern show any missing or erratic signals?

Yes

>> Replace the APP Sensor Assembly per Service Information. After installation is complete, use a scan

tool and select the ETC RELEARN function to relearn the APPS values.

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

No

>> Go To 9

9.

PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.

Were there any problems found?

Yes

>> Repair as necessary.

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

No

>> Replace and program the Powertrain Control Module per Service Information.

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

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

DR/DH

P2161-VEHICLE SPEED SENSOR 2 ERRATIC

DR/DH

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

9 - 907

P2161-VEHICLE SPEED SENSOR 2 ERRATIC (CONTINUED)

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

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
Ignition on.

•

Set Condition:
PCM recognizes Vehicle speed input No.2 erratic or high. VSS No.2 is based on the average of the Front
Wheel Speeds. One trip fault and the code will set within 5 seconds. No MIL and No ETC light. Cruise is
disabled.

Possible Causes

(B222) VEHICLE SPEED NO.2 SIGNAL CIRCUIT SHORTED TO VOLTAGE

(B222) VEHICLE SPEED NO.2 SIGNAL CIRCUIT OPEN

(B222) VEHICLE SPEED NO.2 SIGNAL CIRCUIT SHORTED TO GROUND

TIRE CIRCUMFERENCE

PCM

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

Diagnostic Test

1.

ACTIVE DTC

Ignition on, engine not running.

NOTE: Check for any Bus Communication DTCs. If no Bus or Communication DTCs are set, check for active
DTCs stored in the Ant-Lock Brake Module. Any bus or communication DTCs or VSS DTCs in the Ant-Lock
Brake Module must be properly diagnosed before continuing.
With a scan tool, read DTCs.

Is the DTC active at this time?

Yes

>> Go To 2

No

>> Refer to the INTERMITTENT CONDITION Diagnostic Procedure.

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

2.

VISUAL INSPECTION

NOTE: This code can set due to tire circumference differences and from the front or rear wheels being on
a slippery surface while the opposite tires are not.
This code may also set on a hard acceleration on loose gravel or during other off road driving conditions.

Check tire pressure of all the tires.

Check tire wear on all the tires.

Ask the customer what the road and driving conditions were like when the fault set.

Were any problems found?

Yes

>> Repair as necessary. If the code set during a front OR rear wheel spin condition, no repair is necessary.

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

No

>> Go To 3

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

DR/DH

P2161-VEHICLE SPEED SENSOR 2 ERRATIC (CONTINUED)

3.

(B222) VEHICLE SPEED NO.2 SIGNAL CIRCUIT SHORTED TO VOLTAGE

Turn the ignition off.

Disconnect the ABS Module harness connector.

Disconnect the C1 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.
Ignition on, engine not running.

Measure the voltage of the (B222) Vehicle Speed No.2 Signal circuit at
the appropriate terminals of special tool #8815.

Is the voltage above 6.0 volts?

Yes

>> Repair the short to voltage in the (B222) Vehicle Speed

No.2 Signal circuit.

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

No

>> Go To 4

4.

(B222) VEHICLE SPEED NO.2 SIGNAL CIRCUIT OPEN

Turn the ignition off.

Measure the resistance of the (B222) Vehicle Speed No.2 Signal cir-
cuit from the ABS Module harness connector to the appropriate termi-
nal special tool #8815.

Is the resistance below 5.0 ohms?

Yes

>> Go To 5

No

>> Repair the open in the (B222) Vehicle Speed No.2 Signal

circuit.

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

DR/DH

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

9 - 909