Page 3657 of 5267

cuits. If no problems are found, replace and program the ECM per the ServiceInformation. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
10.CHECK THE (T16) TRANSMISSION CONTROL OUTPUT CIRCUIT FOR OPEN.
Ignition on, engine not running.
Using the scan tool in the TIPM, actuate the Transmission.
Using a 12-volt test light connected to ground, back probe the (T16)
Transmission Control Output circuit at the TIPM C10 harness connector.
Does the test light cycle on and off and illuminate brightly?
Ye s>>
Go To 11
No>>
Using the schematics as a guide, check the Totally Inte-
grated Power Module (TIPM) pins, terminals, and connec-
tors for corrosion, damage, or terminal push out. Pay
particular attention to all power and ground circuits. If no
problems are found, replace and program the TIPM per the
Service Information.
11 .CHECK THE (T515) TRANSMISSION CONTROL CIRCUIT
Turn the ignition off to the lock position.
Disconnect the TIPM C1 harness connector.
Ignition on, engine not running.
Using the scan tool in the ECM, actuate the Transmission.
Using a 12-volt test light connected to ground, check the (T515) Trans-
mission Control circuit at the TIPM C1 harness connector.
Does the test light cycle on and off and illuminate brightly?
Ye s>>
Using the schematics as a guide, check the Totally Inte-
grated Power Module (TIPM) pins, terminals, and connec-
tors for corrosion, damage, or terminal push out. Pay
particular attention to all power and ground circuits. If no
problems are found, replace and program the TIPM per the
Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 12
Page 3658 of 5267

12.CHECK THE (T515) TRANSMISSION CONTROL CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Disconnect the ECM C2 harness connector.
Connect a jumper wire between cavity 5 in the ECM C2 harness con-
nector and ground.
Using a 12-volt test light connected to 12 volts, check the (T515) Trans-
mission Control circuit at the TIPM C1 harness connector.
Does the test light illuminate brightly?
Ye s>>
Using the schematics as a guide, check the Engine Control
Module (ECM) pins, terminals, and connectors for corrosion,
damage, or terminal push out. Pay particular attention to all
power and ground circuits. If no problems are found,
replace and program the ECM per the Service Information.
(Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/ENGINE CONTROL MODULE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Repair the (T515) Transmission Control circuit for an open.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
13.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Use the Freeze Frame Data to help duplicate the conditions in which the DTC originally set. Pay particular attention
to the DTC set conditions, such as, VSS, MAP, ECT, and Load
Using the schematics as a guide, visually inspect the related wiring harness. Look for any chafed, pierced, pinched,
or partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken,bent, pushed out, or corroded terminals.
Wiggle the wiring and connectors while checking for any possible open or shorted circuits.
Check for any Service Information Tune-ups or Technical Service Bulletins that may apply.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
Page 3659 of 5267
P0850-P/N SWITCH PERFORMANCE (DIESEL)
For a complete wiring diagramRefer to Section 8W
Page 3660 of 5267

When Monitored:
Continuously with the ignition on and engine running.
Set Condition:
The Transmission governor pressure set point is above a threshold while inparkortheP/Nswitchisindrive
during an engine start.
Possible Causes
TRS CONNECTOR DAMAGE OR CORROSION
ECM CONNECTOR DAMAGE OR CORROSION
(T41) P/N POSITION SWITCH SENSE CIRCUIT OPEN
(T41) P/N POSITION SWITCH SENSE CIRCUIT SHORT TO GROUND
(T41) P/N POSITION SWITCH SENSE CIRCUIT SHORT TO ANOTHER CIRCUIT
TRANSMISSION RANGE SENSOR
ENGINE CONTROL MODULE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
Diagnostic Test
1.CHECK IF THE SCAN TOOL DISPLAYS P/N AND D/R IN THE CORRECT POSITION
Ignition on, engine not running.
With the scan tool, monitor the PNP switch input state.
Move the gear selector through all gear positions Park to 1st and back to Park.
Did the scan tool display P/N and D/R in the correct gear positions?
Ye s>>
Go To 8
No>>
Go To 2
2.CHECK THE TRS CONNECTOR FOR DAMAGE OR CORROSION
Turn the ignition off to the lock position.
Disconnect the Transmission Range Sensor harness connector.
Inspect the Transmission Range Sensor harness wiring and connector for damage, pushed out pins, or corrosion,
etc.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 3
3.CHECK THE ECM CONNECTOR FOR DAMAGE OR CORROSION
Disconnect the ECM C2 harness connector.
Inspect the ECM wiring and connector for damage, pushed out pins, or corrosion, etc.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Go To 4
Page 3661 of 5267
4.CHECK THE (T41) P/N POSITION SWITCH SENSE CIRCUIT FOR AN OPEN
Measure the resistance of the (T41) P/N Position Switch Sense circuit
between the ECM C2 harness connector and the Transmission Range
Sensor harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 5
No>>
Repair the (T41) P/N Position Switch Sense circuit for an
open.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
5.CHECK THE (T41) P/N POSITION SWITCH SENSE CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between ground and the (T41) P/N Position
Switch Sense circuit.
Is the resistance greater then 100k ohms?
Ye s>>
Go To 6
No>>
Repair the (T41) P/N Position Switch Sense circuit for a
short to ground.
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
Page 3662 of 5267

6.CHECK THE (T41) P/N POSITION SWITCH SENSE CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
Measure the resistance between the (T41) P/N Position Switch Sense
circuit and all other circuits in the ECM C1 and C2 harness connectors.
Is the resistance greater 100k ohms between the (T41) P/N
Position Switch Sense circuitand any other circuit(s) in the
ECM C1 and C2 harness connectors?
Ye s>>
Go To 7
No>>
Repair the (T41) P/N Position Switch Sense circuit for a
short to another circuit(s).
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
7.CHECK THE TRANSMISSION RANGE SENSOR
Reconnect the Transmission Range Sensor harness connector.
Move the gear selector through all gear positions, from Park to 1st and
back.
While moving the gear selector through the gear positions, measure the
resistance between ground and the (T41) P/N Position Switch Sense
circuit in the ECM harness connector.
NOTE: The circuit is grounded in Park and Neutral and open in the
other positions.
Did the display change from above 100k ohms (open) to below
5.0 ohms (grounded)?
Ye s>>
Using the schematics as a guide, check the Engine Control
Module (ECM) pins, terminals, and connectors for corrosion,
damage, or terminal push out. Pay particular attention to all
power and ground circuits. If no problems are found,
replace and program the ECM per the Service Information.
(Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/ENGINE CONTROL MODULE - REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER -
1 (DIESEL). (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Replace the Transmission Range Sensor per Service Infor-
mation. (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 48RE/TRANSMISSION RANGE SENSOR -
REMOVAL)
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
Page 3663 of 5267
8.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Use the Freeze Frame Data to help duplicate the conditions in which the DTC originally set. Pay particular attention
to the DTC set conditions, such as, VSS, MAP, ECT, and Load
Using the schematics as a guide, visually inspect the related wiring harness. Look for any chafed, pierced, pinched,
or partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken,bent, pushed out, or corroded terminals.
Wiggle the wiring and connectors while checking for any possible open or shorted circuits.
Check for any Service Information Tune-ups or Technical Service Bulletins that may apply.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 48RE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
Page 3664 of 5267
P0868-GOVERNOR PRESSURE SENSOR VOLTS TOO HI (DIESEL)
For a complete wiring diagramRefer to Section 8W