Page 79 of 5267
P127C-FUEL PUMP CONTROL CIRCUIT 2 LOW
For a complete wiring diagramRefer to Section 8W.
Page 82 of 5267
P127D-FUEL PUMP CONTROL CIRCUIT 2 HIGH
For a complete wiring diagramRefer to Section 8W.
Page 86 of 5267
P127E-FUEL PUMP CONTROL CIRCUIT 2 OPEN (TIPM)
For a complete wiring diagramRefer to Section 8W.
Page 90 of 5267
P0127F-FUEL PUMP CONTROL CIRCUIT 2 OVERCURRENT (TIPM)
For a complete wiring diagramRefer to Section 8W.
Page 91 of 5267

When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts. TIPM requesting Fuel Pump operation.
Set Condition:
An overcurrent condition is detected in the fuel pump control output circuit. One Trip Fault. Three good trips to
turn off the MIL.
Possible Causes
TERMINAL DAMAGE OR CORROSION
FUEL PUMP MOTOR GROUND HIGH RESISTANCE
(A109) FUEL PUMP CONTROL OUTPUT CIRCUIT HIGH RESISTANCE
FUEL PUMP MOTOR
TIPM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.FUEL PUMP OPERATION
Ignition on, engine not running.
With a scan tool in the TIPM Actuators, actuate the Fuel Pump.
Is the Fuel Pump operating?
Ye s>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 2
2.VISUAL AND PHYSICAL CONNECTOR AND TERMINAL INSPECTION
Turn the ignition off.
Disconnect the C10 TIPM harness connector.
Disconnect the Fuel Pump Module harness connector.
Inspect the terminal and connector condition. Check for signs of corrosion build up or damage the would compro-
mise the terminal to controller pin connector.
NOTE: Make sure that all in-line connectors are inspected for corrosion and/or damage.
Visually inspect the wiring harness. Look for any chafed, pierced, pinched or partially broken wires hidden in the
wire insulation.
Were any of the above conditions found?
Ye s>>
Repair or replace as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
Page 93 of 5267
P01404-EGR POSITION SENSOR RATIONALITY CLOSED
For a complete wiring diagramRefer to Section 8W.
Page 98 of 5267

For a complete wiring diagramRefer to Section 8W.
Theory of Operation
When all criteria has been met, power is supplied to each MDS Solenoid when the engine is making a transition
from 8 cylinder mode to 4 cylinder mode. By actuating the solenoid, oil pressure is raised to the pair of lifters that
coincide with each particular solenoid. The oil pressure pushes in the locking pins that allows the lifter to collapse,
decoupling the valves and camshaft.
When Monitored:
Transition from 8 to 4 cylinder mode.
Set Condition:
The MDS fails to active and take place for cylinder 1. One trip fault.
Possible Causes
(K451) MDS SOLENOID NO.1 CONTROL SHORT TO GROUND
(K451) MDS SOLENOID NO.1 CONTROL OPEN
(Z42) GROUND CIRCUIT OPEN
INSUFFICIENT OIL PRESSURE ACTING ON THE LIFTER LOCKING PINS
OIL PASSAGES RESTRICTED
LIFTER
MDS SOLENOID NO.1
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?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 103 of 5267

For a complete wiring diagramRefer to Section 8W.
Theory of Operation
When all criteria has been met, power is supplied to each MDS Solenoid when the engine is making a transition
from 8 cylinder mode to 4 cylinder mode. By actuating the solenoid, oil pressure is raised to the pair of lifters that
coincide with each particular solenoid. The oil pressure pushes in the locking pins that allows the lifter to collapse,
decoupling the valves and camshaft.
When Monitored:
Transition from 8 to 4 cylinder mode.
Set Condition:
The MDS fails to active and take place for cylinder 4. One trip fault.
Possible Causes
(K452) MDS SOLENOID NO.4 CONTROL SHORT TO GROUND
(K452) MDS SOLENOID NO.4 CONTROL OPEN
(Z42) GROUND CIRCUIT OPEN
INSUFFICIENT OIL PRESSURE ACTING ON THE LIFTER LOCKING PINS
OIL PASSAGES RESTRICTED
LIFTER
MDS SOLENOID NO.4
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?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)