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)
Page 834 of 5267
P2128-PPS 2 VOLTAGE TOO HIGH
For a complete wiring diagramRefer to Section 8W.
Page 835 of 5267

When Monitored:
While the key is on and during engine operation.
Set Condition:
The APPS signal circuit voltage at the ECM goes above 4.24 volts for more than 2 seconds.
Possible Causes
(K400) APPS NO. 1 RETURN CIRCUIT OPEN
(K29) APPS NO. 2 SIGNAL CIRCUIT SHORTED TO (K854) APPS NO. 2 5-VOLT SUPPLY
(K29) APPS SIGNAL CIRCUIT SHORTED TO ANOTHER CIRCUIT
ECM
APPS
INTERMITTENT CONDITION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.(K400) APPS NO. 2 RETURN CIRCUIT OPEN
Turn the ignition off.
Disconnect the APPS harness connector.
Disconnect the ECM harness connectors.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance on the (K400) APPS No. 2 return circuit
between the sensor harness connector and the ECM harness connec-
tor.
Is the resistance less than 10 ohms?
Ye s>>
Go To 2
No>>
Repair the (K400) APPS No. 2 return circuit open.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 836 of 5267

2.(K29) APPS NO. 2 SIGNAL CIRCUIT SHORTED TO (F856)APPS NO. 1 5-VOLT SUPPLY
Measure the resistance between the (K29) APPS No. 2 signal circuit in
the sensor harness connector andthe (F856)APPS No. 2 5-volt supply
circuit in the sensor harness connector.
Is the resistance greater than 100 K ohms?
Ye s>>
Go To 3
No>>
Repair the (K29) APPS No. 2 signal circuit shorted to the
(F856)5-volt supply circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
3.(K29) APPS SIGNAL CIRCUIT SHORTED TO ANOTHER CIRCUIT
Measure the resistance between the APPS No. 2 signal circuit at the
ECM harness connector and all other circuits in the ECM harness con-
nector.
Is the resistance greater than 100 k ohms?
Ye s>>
Go To 4
No>>
Repair the (K29) APPS No. 2 signal circuit shorted to
another circuit in the engine harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 837 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 838 of 5267
P2146-BANK 1 (CYLINDERS 1-3) SHORTED HIGH OR LOW
For a complete wiring diagramRefer to Section 8W.
Page 839 of 5267

When Monitored:
While the engine is running.
Set Condition:
A circuit failure detected at cylinders 1,2, or 3 or any combination of cylinders 1,2, or 3.
Possible Causes
OTHER DTC’S
HIGH SIDE DRIVER CIRCUIT OPEN
LOW SIDE DRIVER CIRCUIT OPEN
HIGH SIDE DRIVER SHORTED TO LOW SIDE DRIVER
HIGH SIDE DRIVERS SHORTED LOW
LOW SIDE DRIVER CIRCUIT SHORTED OTHER LOW SIDE DRIVER CIRCUIT
LOW SIDE DRIVERS SHORTED LOW
HIGH SIDE DRIVER SHORTED TO VOLTAGE
LOW SIDE DRIVER SHORTED TO VOLTAGE
LOW SIDE DRIVER CIRCUIT SHORTED IN INJECTOR HARNESS
INJECTOR
INJECTOR HARNESS
INTERMITTENT CONDITION
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHER DTC’S
With the scan tool, read DTCs.
Do you have any combination of DTC’s P0201, P0202, or P0203?
Ye s>>
Repair other DTC’s first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.HIGH SIDE DRIVER CIRCUIT OPEN
Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the Injector 1-3 harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance of the injector high side driver circuit between
the Bank 1 high side driver circuit in the ECM harness connector and
the high side driver circuit in the injector harness connectors for cylin-
ders 1-3.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 3
No>>
Repair the open high side driver circuit from ECM harness
connector to the Injector harness connector.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
Page 840 of 5267
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
3.LOW SIDE DRIVER CIRCUIT OPEN
Measure the resistance of the #1,#2, and #3 injector low side driver cir-
cuits between the ECM harness connector and the injector harness
connectors.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 4
No>>
Repair the open low side driver circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
4.HIGH SIDE DRIVER SHORTED TO LOW SIDE DRIVER
Measure the resistance between the Bank 1 high side driver circuit at
the ECM harness connector and the low side driver circuit for injectors
1-3 at the ECM harness connector.
Istheresistancemorethan100kOhms?
Ye s>>
Go To 5
No>>
RepairtheHighsidecircuitshortedtothelowsidecircuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)