Dodge Ram Truck 1500-2500-3500. Manual — part 965

P1604-PCM INTERNAL DUAL-PORT RAM READ/WRITE INTEGRITY FAILURE (CONTINUED)

2.

PCM

The Powertrain Control Module is reporting internal errors.

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

P1607-PCM INTERNAL SHUTDOWN TIMER RATIONALITY

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 and battery voltage greater than 10 volts.

•

Set Condition:
Internal PCM failure detected. One Trip Fault. Three good trips to turn off the MIL.

Possible Causes

PCM FUSED IGNITION SWITCH CIRCUIT

PCM INTERNAL

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

Diagnostic Test

1.

PCM IGNITION CIRCUITS

Turn the ignition off.

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.
With a 12-volt test light connected to ground and with special tool
#8815 installed, probe the (F202), (F1), and (T751) Fused Ignition
Switch circuits.

Perform the above check with the Ignition key in the off lock position,
Ignition on, engine not running position, and during cranking.

Wiggle the related wire harness while probing the special tool with the
test light to try to interrupt the circuit.

Does the test light illuminate brightly?

Yes

>> Go To 2

No

>> Repair the open or excessive resistance in the (F202), (F1), and (T751) Fused Ignition Switch (Off, Run,

Start) circuits. Inspect the related fuse, if the fuse is open check the circuits for a short to ground.

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

2.

PCM

The Powertrain Control Module is reporting internal errors.

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)

DR/DH

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

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P1618-SENSOR REFERENCE VOLTAGE 1 CIRCUIT ERRATIC

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

DR/DH

P1618-SENSOR REFERENCE VOLTAGE 1 CIRCUIT 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:
When the PCM recognizes the Primary 5-volt Supply circuit voltage is varying too much too quickly. One Trip
Fault. ETC light is flashing.

Possible Causes

(F855) PRIMARY 5-VOLT SUPPLY SHORTED TO GROUND

(F855) PRIMARY 5-VOLT SUPPLY SHORTED TO BATTERY VOLTAGE

(F855) PRIMARY 5-VOLT SUPPLY CIRCUIT OPEN

5-VOLT SENSOR

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.

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.

(F855) PRIMARY 5-VOLT SUPPLY CIRCUIT SHORTED TO
GROUND

Turn the ignition off.

Disconnect the C2 PCM harness connector.

Disconnect all the Sensors that share the (F855) Primary 5-volt Supply
circuit.

NOTE: This code can be caused by the improper installation of
after market accessories that may be causing excessive noise on
the (F855) 5-volt Supply circuit.
Measure the resistance between ground and the (F855) Primary 5-volt
Supply circuit in the CKP Sensor harness connector.

Is the resistance below 100 ohms?

Yes

>> Repair the short to ground in the (F855) Primary 5-volt

Supply circuit.

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

No

>> Go To 3

DR/DH

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

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