Page 793 of 5267

3.(A109) FUEL PUMP CONTROL OUTPUT CIRCUIT SHORTED TO GROUND
Turn the ignition off
Disconnect the C10 TIPM harness connector.
Disconnect the Fuel Pump Module harness connector.
Measure the resistance between ground and the (A109) Fuel Pump
Control Output circuit at the Fuel Pump Module harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (A109) Fuel Pump Control
Output circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.FUEL PUMP MODULE
Connect the C1 and C10 TIPM harness connectors.
Ignition on, engine not running.
Using the scan tool under the TIPM Actuators, actuate the Fuel Pump.
With a 12-volt test light connected to ground, probe the (A109) Fuel
Pump Control Output circuit at the Fuel Pump Module harness connec-
tor.
Does the test light illuminate brightly and flash on and off?
Ye s>>
Replace the Fuel Pump Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
5.TOTALLY INTEGRATED POWER MODULE
NOTE: Before continuing, check the TIPM 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 any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace the Totally Integrated Power Module per Service Information.
Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES - STANDARD PROCEDURE)
Page 796 of 5267

3.(A109) FUEL PUMP CONTROL OUTPUT CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off
Disconnect the C10 TIPM harness connector.
Disconnect the Fuel Pump Module harness connector.
Ignition on, engine not running.
Using a 12-volt test light connected to ground, probe the (A109) Fuel
Pump Control Output circuit at the Fuel Pump Module harness connec-
tor.
Does the test light illuminate brightly?
Ye s>>
Repair the short to battery voltage in the (A109) Fuel Pump
Control Output circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.FUEL PUMP GROUND CIRCUITS OPEN
Turn the ignition off.
Connect the C1 and C10 TIPM harness connectors.
Using a 12-volt test light connected to 12-volts, probe the (Z927) and
(Z210) Fuel Pump ground circuits at the Fuel Pump Module harness
connector.
Does the test light illuminate brightly?
Ye s>>
Go To 5
No>>
Repair the excessive resistance in the Fuel Pump ground
circuits.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
5.FUEL PUMP MODULE
Ignition on, engine not running.
Using the scan tool under the TIPM Actuators, actuate the Fuel Pump.
With a 12-volt test light connected to ground, probe the (A109) Fuel
Pump Control Output circuit at the Fuel Pump Module harness connec-
tor.
Does the test light illuminate brightly and flash on and off?
Ye s>>
Replace the Fuel Pump Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 6
Page 797 of 5267
6.TOTALLY INTEGRATED POWER MODULE
NOTE: Before continuing, check the TIPM 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 any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace the Totally Integrated Power Module per Service Information.
Perform the BODY VERIFICATION TEST – VER 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 801 of 5267
5.TOTALLY INTEGRATED POWER MODULE
NOTE: Before continuing, check the TIPM 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 any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace the Totally Integrated Power Module in accordance with the Service Information.
Perform the BODY VERIFICATION TEST – VER 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 804 of 5267

3.(A109) FUEL PUMP CONTROL OUTPUT CIRCUIT HIGH RESISTANCE
With a jumper wire, connect one end to the (A109) Fuel Pump Control
Output circuit in the Fuel Pump Module harness connector and the
other to a clean chassis ground.
Using a 12-volt test light to battery voltage, probe the (A109) Fuel Pump
Control Output circuit in the C10 TIPM harness connector.
NOTE: The test light should be illuminated and bright. Compared
the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly.
Ye s>>
Go To 4
No>>
Repair the excessive resistance in the (A109) Fuel Pump
Control Output circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE).
4.FUEL PUMP MOTOR GROUND CIRCUITS
Using a 12-volt test light to battery voltage, probe the (Z927) and (Z210)
Fuel Pump Motor Ground circuits in the Fuel Pump Motor harness con-
nector.
NOTE: The test light should be illuminated and bright. Compared
the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly.
Ye s>>
Go To 5
No>>
Repair the excessive resistance in the Fuel Pump Motor
Ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
5.FUEL PUMP CONTROL OUTPUT FROM TIPM
Reconnect the C10 TIPM harness connector.
Ignition on, engine not running.
With a scan tool in the TIPM Actuators, actuate the Fuel Pump.
Using the 12-Volt test light connected to ground, probe the (A109) Fuel
Pump Control Output circuit in the Fuel Pump Module harness connec-
tor.
Does the test light illuminate brightly?
Ye s>>
Replace the Fuel Pump Module
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace the TIPM in accordance with the Service Informa-
tion.
Perform the BODY VERIFICATION TEST – VER 1. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
Page 824 of 5267

6.(F855) APPS NO. 1 5-VOLT SUPPLY CIRCUIT SHORTED TO OTHER CIRCUITS
Measure the resistance between the (F855) APPS No. 1 5-volt supply
circuit at the sensor harness connector and all other circuits in the ECM
harness connector.
Is the resistance greater than 100 k ohms?
Ye s>>
Go To 7
No>>
Repair the (F855) APPS No. 1 5-volt supply circuit shorted
to other circuits.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
7.ECM
Reconnect the ECM harness connectors.
Turn the ignition on.
While monitoring with the scan tool, connect a jumper wire between the (K23) APPS No. 1 signal circuit at the
sensor harness connector and the (F855) APPS No. 1 5-volt supply circuit atthe sensor harness connector.
NOTE: With the sensor disconnected it is normal to have a APPS 1 and APPS 2 lowvoltage DTC set.
Did DTC P2123 set?
Ye s>>
Go To 8
No>>
Replace and program the ECM in accordance with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
8.APPS
Reconnect the APPS harness connector.
Monitor the APPS 1 and APPS 2 voltage with the scan tool while depressing thethrottle pedal.
Is the voltage transition shown on the scan tool smooth while depressing thethrottleandisthevolta
Ye s>>
Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
No>>
Replace the APPS.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 828 of 5267

4.ECM
Reconnect the ECM harness connectors.
Reconnect the APPS harness connector.
While monitoring with the scan tool, disconnect the sensor connector.
Did a APPS No. 1 and APPS No. 2 voltage too low DTC set?
Ye s>>
Go To 5
No>>
Replace and program the ECM in accordance with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
5.APPS
Reconnect the APPS harness connector.
Monitor the APPS No. 1 and APPS No. 2 voltage with the scan tool while depressing the throttle pedal.
Is the voltage transition shown on the scan tool smooth while depressing thethrottleandisthevolt-
age from APPS 1 twice as much as from APPS2?
Ye s>>
Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
No>>
Replace the APPS.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 833 of 5267

6.(F856) APPS NO. 2 5-VOLT SUPPLY CIRCUIT SHORTED TO OTHER CIRCUITS
Measure the resistance between the (F856) APPS No. 2 5-volt supply
circuit at the sensor harness connector and all other circuits in the ECM
harness connector.
Is the resistance greater than 100 k ohms?
Ye s>>
Go To 7
No>>
Repair the (F856) APPS No. 2 5-volt supply circuit shorted
to other circuits.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
7.ECM
Reconnect the ECM harness connectors.
Turn the ignition on.
While monitoring with the scan tool, connect a jumper wire between the (K29) APPS No. 2 signal circuit at the
sensor harness connector and the (F856) APPS No. 2 5-volt supply circuit atthe sensor harness connector.
NOTE: With the sensor disconnected it is normal to have a APPS 1 and APPS 2 lowvoltage DTC set.
Did DTC P2128 set?
Ye s>>
Go To 8
No>>
Replace and program the ECM in accordance with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
8.APPS
Reconnect the APPS harness connector.
Monitor the APPS 1 and APPS 2 voltage with the scan tool while depressing thethrottle pedal.
Is the voltage transition shown on the scan tool smooth while depressing thethrottleandisthevolt-
age swing smooth?
Ye s>>
Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
No>>
Replace the APPS.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)