
Symptom:
P1767-TRANSMISSION RELAY ALWAYS ON
When Monitored and Set Condition:
P1767-TRANSMISSION RELAY ALWAYS ON
When Monitored: When ignition key is turned from the OFF position to the RUN position
and/or ignition is turned from the CRANK position to RUN position.
Set Condition: This DTC is set if the Transmission Control Module senses greater than
3 volts at the Transmission Control Relay Output terminal of the TCM prior to the TCM
energizing the relay.
POSSIBLE CAUSES
INTERMITTENT WIRING AND CONNECTORS
TRANSMISSION CONTROL RELAY STUCK CLOSED
TRANSMISSION CONTROL RELAY OUTPUT CIRCUIT SHORT TO VOLTAGE
TRANSMISSION RELAY CONTROL CIRCUIT SHORT TO VOLTAGE
TCM - TRANSMISSION RELAY ALWAYS ON
TEST ACTION APPLICABILITY
1NOTE: Low fluid level can be the cause of many Transmission problems. If
the fluid level is low locate and repair the leak then check and adjust the
fluid level per the Service Information.
NOTE: Always perform diagnostics with a fully charged battery to avoid
false symptoms.
With the DRBIIIt, read the engine DTC's. Check and repair all engine DTC's prior
to performing Transmission Symptom Diagnostics.
With the DRBIIIt, read Transmission DTC's. Record all DTC's and 1 Trip Failures.
NOTE: Diagnose 1 Trip Failures as a fully matured DTC.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
Repair as necessary.
Perform the Shift Lever Position Test. If the test does not pass, refer to Symptom test
for P0705 Check Shifter Signal.
For Gear Ratio DTC's, check and record all CVI's.
Most DTC's set on start up but some must be set by driving the vehicle such that all
diagnostic monitors have run.
NOTE: Verify flash level of Transmission Control Module. Some problems
are corrected by software upgrades to the Transmission Control Module.
NOTE: Check for applicable TSB's related to the symptom.
Perform this procedure prior to Symptom diagnosis.All
Continue
Go To 2
89
TRANSMISSION

Symptom:
P1768-RELAY OUTPUT ALWAYS OFF
When Monitored and Set Condition:
P1768-RELAY OUTPUT ALWAYS OFF
When Monitored: Continuously
Set Condition: This code is set when less than 3 volts are present at the transmission
control relay output circuits at the Transmission Control Module when the TCM is
energizing the relay.
POSSIBLE CAUSES
INTERMITTENT WIRING AND CONNECTORS
FUSED B+ CIRCUIT OPEN
TRANSMISSION CONTROL RELAY OUTPUT CIRCUIT OPEN
TRANSMISSION RELAY CONTROL CIRCUIT OPEN
TRANSMISSION CONTROL RELAY GROUND CIRCUIT OPEN
TRANSMISSION CONTROL RELAY STUCK OPEN
TRANSMISSION CONTROL RELAY OUTPUT CIRCUIT SHORT TO GROUND
TRANSMISSION RELAY CONTROL CIRCUIT SHORT TO GROUND
TCM - TRANSMISSION CONTROL RELAY ALWAYS OFF
TEST ACTION APPLICABILITY
1NOTE: Low fluid level can be the cause of many Transmission problems. If
the fluid level is low locate and repair the leak then check and adjust the
fluid level per the Service Information.
NOTE: Always perform diagnostics with a fully charged battery to avoid
false symptoms.
With the DRBIIIt, read the engine DTC's. Check and repair all engine DTC's prior
to performing Transmission Symptom Diagnostics.
With the DRBIIIt, read Transmission DTC's. Record all DTC's and 1 Trip Failures.
NOTE: Diagnose 1 Trip Failures as a fully matured DTC.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
Repair as necessary.
Perform the Shift Lever Position Test. If the test does not pass, refer to Symptom test
for P0705 Check Shifter Signal.
For Gear Ratio DTC's, check and record all CVI's.
Most DTC's set on start up but some must be set by driving the vehicle such that all
diagnostic monitors have run.
NOTE: Verify flash level of Transmission Control Module. Some problems
are corrected by software upgrades to the Transmission Control Module.
NOTE: Check for applicable TSB's related to the symptom.
Perform this procedure prior to Symptom diagnosis.All
Continue
Go To 2
92
TRANSMISSION

Symptom:
P1775-SOLENOID SWITCH VALVE LATCHED IN TCC POSITION
When Monitored and Set Condition:
P1775-SOLENOID SWITCH VALVE LATCHED IN TCC POSITION
When Monitored: During an attempted shift into 1st gear.
Set Condition: This DTC is set if three unsuccessful attempts are made to shift into 1st
gear in one given ignition start.
POSSIBLE CAUSES
INCORRECT FLUID LEVEL
RELATED DTC P1784 PRESENT
INTERMITTENT OPERATION
TRANSMISSION CONTROL RELAY OUTPUT CIRCUIT OPEN
L/R PRESSURE SWITCH SENSE CIRCUIT OPEN
L/R PRESSURE SWITCH CIRCUIT SHORT TO GROUND
L/R PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
INTERNAL TRANSMISSION - SOLENOID SWITCH VALVE STUCK
TCM - SOLENOID SWITCH VALVE
TEST ACTION APPLICABILITY
1NOTE: Low fluid level can be the cause of many Transmission problems. If
the fluid level is low locate and repair the leak then check and adjust the
fluid level per the Service Information.
NOTE: Always perform diagnostics with a fully charged battery to avoid
false symptoms.
With the DRBIIIt, read the engine DTC's. Check and repair all engine DTC's prior
to performing Transmission Symptom Diagnostics.
With the DRBIIIt, read Transmission DTC's. Record all DTC's and 1 Trip Failures.
NOTE: Diagnose 1 Trip Failures as a fully matured DTC.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
Repair as necessary.
Perform the Shift Lever Position Test. If the test does not pass, refer to Symptom test
for P0705 Check Shifter Signal.
For Gear Ratio DTC's, check and record all CVI's.
Most DTC's set on start up but some must be set by driving the vehicle such that all
diagnostic monitors have run.
NOTE: Verify flash level of Transmission Control Module. Some problems
are corrected by software upgrades to the Transmission Control Module.
NOTE: Check for applicable TSB's related to the symptom.
Perform this procedure prior to Symptom diagnosis.All
Continue
Go To 2
96
TRANSMISSION

TEST ACTION APPLICABILITY
2 With the DRBIIIt, check for other Transmission DTC's
Is DTC P1784 present also?All
Ye s®Refer to symptom list and perform test for DTC P1784.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
No®Go To 3
3 Perform a visual inspection of all connectors, wiring, and cooler connections before
proceeding. Repair as necessary.
With the DRBIIIt, Check the STARTS SINCE SET counter.
NOTE: This counter only applies to the last DTC set.
Is the STARTS SINCE SET counter 2 or less?All
Ye s®Go To 4
No®Go To 12
4 Turn the ignition off to the lock position.
CAUTION: Remove the Starter Relay from the IPM. This will prevent the
vehicle from being started in gear.
Install Transmission Simulator, Miller tool #8333 and the FWD Adapter Cable kit,
Miller tool #8333-1.
Ignition on, engine not running.
On the Transmission Simulator select L/R on the Pressure Switch selector switch.
With the DRBIIIt, monitor the L/R Pressure Switch state while pressing the
Pressure Switch Test button on the Transmission Simulator.
Did the Pressure Switch state change from OPEN to CLOSED when the test button
was pressed?All
Ye s®Go To 5
No®Go To 7
5 Check the Transmission Fluid Level per the Service Information.
Is the Transmission Fluid Level at the proper level?All
Ye s®Go To 6
No®Adjust fluid level and repair cause of incorrect fluid level.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
6 If there are no possible causes remaining, view repair. All
Repair
Inspect the Solenoid Switch Valve per service information and
repair or replace as necessary. If no problems are found, replace
the Transmission Solenoid/Pressure Switch assembly per Service
Information.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
97
TRANSMISSION
P1775-SOLENOID SWITCH VALVE LATCHED IN TCC POSITION Ð
Continued

Symptom:
P1776-SOLENOID SWITCH VALVE LATCHED IN LR POSITION
When Monitored and Set Condition:
P1776-SOLENOID SWITCH VALVE LATCHED IN LR POSITION
When Monitored: Continuously when doing partial or full EMCC (PEMCC or FEMCC).
Set Condition: This DTC will set if the TCM senses the L/R Pressure Switch closing while
performing PEMCC or FEMCC or after two unsuccessful attempts to perform PEMCC or
FEMCC.
POSSIBLE CAUSES
INCORRECT FLUID LEVEL
RELATED DTC P1784 PRESENT
INTERMITTENT OPERATION
TRANSMISSION RELAY OUTPUT CIRCUIT OPEN
L/R PRESSURE SWITCH SENSE CIRCUIT OPEN
L/R PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
L/R PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
INTERNAL TRANSMISSION - SOLENOID SWITCH VALVE STUCK
TCM - SOLENOID SWITCH VALVE
TEST ACTION APPLICABILITY
1NOTE: Low fluid level can be the cause of many Transmission problems. If
the fluid level is low locate and repair the leak then check and adjust the
fluid level per the Service Information.
NOTE: Always perform diagnostics with a fully charged battery to avoid
false symptoms.
With the DRBIIIt, read the engine DTC's. Check and repair all engine DTC's prior
to performing Transmission Symptom Diagnostics.
With the DRBIIIt, read Transmission DTC's. Record all DTC's and 1 Trip Failures.
NOTE: Diagnose 1 Trip Failures as a fully matured DTC.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
Repair as necessary.
Perform the Shift Lever Position Test. If the test does not pass, refer to Symptom test
for P0705 Check Shifter Signal.
For Gear Ratio DTC's, check and record all CVI's.
Most DTC's set on start up but some must be set by driving the vehicle such that all
diagnostic monitors have run.
NOTE: Verify flash level of Transmission Control Module. Some problems
are corrected by software upgrades to the Transmission Control Module.
NOTE: Check for applicable TSB's related to the symptom.
Perform this procedure prior to Symptom diagnosis.All
Continue
Go To 2
100
TRANSMISSION

TEST ACTION APPLICABILITY
2 With the DRBIIIt, check for other Transmission DTCs
Is the DTC P1784 present also?All
Ye s®Refer to symptom list and perform test for DTC P1784.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
No®Go To 3
3 Perform a visual inspection of all connectors, wiring, and cooler connections before
proceeding. Repair as necessary.
With the DRBIIIt, Check the STARTS SINCE SET counter.
NOTE: This counter only applies to the last DTC set.
Is the STARTS SINCE SET counter 2 or less?All
Ye s®Go To 4
No®Go To 12
4 Turn the ignition off to the lock position.
CAUTION: Remove the Starter Relay from the IPM. This will prevent the
vehicle from being started in gear.
Install Transmission Simulator, Miller tool #8333 and the FWD Adapter Cable kit,
Miller tool #8333-1.
Ignition on, engine not running.
On the Transmission Simulator select L/R on the Pressure Switch selector switch.
With the DRBIIIt, monitor the L/R Pressure Switch state while pressing the
Pressure Switch Test button on the Transmission Simulator.
Did the Pressure Switch state change from OPEN to CLOSED when the test button
was pressed?All
Ye s®Go To 5
No®Go To 7
5 Check the Transmission Fluid Level per the Service Information.
Is the Transmission Fluid Level at the proper level?All
Ye s®Go To 6
No®If the Transmission Fluid is low, repair any Transmission Fluid
leak as necessary and adjust the Transmission Fluid Level in
accordance with the Service Information.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
6 If there are no possible causes remaining, view repair. All
Repair
Inspect the Solenoid Switch Valve in the valve body per the
Service Information and repair or replace as necessary. If no
problems are found in valve body, replace the Transmission
Solenoid/Pressure Switch Assembly per service information.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
101
TRANSMISSION
P1776-SOLENOID SWITCH VALVE LATCHED IN LR POSITION Ð
Continued

Symptom:
P1781-OD PRESSURE SWITCH SENSE CIRCUIT
When Monitored and Set Condition:
P1781-OD PRESSURE SWITCH SENSE CIRCUIT
When Monitored: Whenever the engine is running.
Set Condition: The appropriate DTC is set if one of the Pressure Switches are open or
closed at the wrong time in a given gear.
POSSIBLE CAUSES
TRANSMISSION RELAY DTCS PRESENT
INTERMITTENT WIRING AND CONNECTORS
TRANSMISSION RELAY OUTPUT CIRCUIT OPEN
O/D PRESSURE SWITCH SENSE CIRCUIT OPEN
O/D PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
O/D PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
O/D PRESSURE SWITCH INOPERATIVE
TCM - O/D PRESSURE SWITCH
TEST ACTION APPLICABILITY
1NOTE: Low fluid level can be the cause of many Transmission problems. If
the fluid level is low locate and repair the leak then check and adjust the
fluid level per the Service Information.
NOTE: Always perform diagnostics with a fully charged battery to avoid
false symptoms.
With the DRBIIIt, read the engine DTC's. Check and repair all engine DTC's prior
to performing Transmission Symptom Diagnostics.
With the DRBIIIt, read Transmission DTC's. Record all DTC's and 1 Trip Failures.
NOTE: Diagnose 1 Trip Failures as a fully matured DTC.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
Repair as necessary.
Perform the Shift Lever Position Test. If the test does not pass, refer to Symptom test
for P0705 Check Shifter Signal.
For Gear Ratio DTC's, check and record all CVI's.
Most DTC's set on start up but some must be set by driving the vehicle such that all
diagnostic monitors have run.
NOTE: Verify flash level of Transmission Control Module. Some problems
are corrected by software upgrades to the Transmission Control Module.
NOTE: Check for applicable TSB's related to the symptom.
Perform this procedure prior to Symptom diagnosis.All
Continue
Go To 2
104
TRANSMISSION

TEST ACTION APPLICABILITY
2 With the DRBIIIt, read Transmission DTC's
Are there any Transmission Control Relay related DTC's P1765, 1767, or 1768
present?All
Ye s®Refer to symptom list and perform the appropriate test for
Transmission Relay related DTC's.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
No®Go To 3
3 With the DRBIIIt, Check the STARTS SINCE SET counter.
NOTE: This counter only applies to the last DTC set.
Is the STARTS SINCE SET counter 2 or less for P1781?All
Ye s®Go To 4
No®Go To 11
4 Turn the ignition off to the lock position.
CAUTION: Remove the Starter Relay from the IPM. This will prevent the
vehicle from being started in gear.
Install Transmission Simulator, Miller tool #8333 and the FWD Adapter Cable kit,
Miller tool #8333-1.
Note: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.
On the Transmission Simulator select OD on the Pressure Switch selector switch.
With the DRBIIIt, monitor the OD Pressure Switch state while pressing the
Pressure Switch Test button on the Transmission Simulator.
Did the Pressure Switch state change from OPEN to CLOSED when the test button
was pressed?All
Ye s®Go To 5
No®Go To 6
5 If there are no possible causes remaining, view repair. All
Repair
Replace Transmission Solenoid/Pressure Switch Assembly per the
Service Information.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
6 Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid/Pressure Switch Assembly harness connector.
Remove the Transmission Control Relay from the IPM.
Note: Check connectors - Clean/repair as necessary.
Connect a jumper wire between the Fused B+ circuit and the Transmission Control
Relay Output circuit in the Transmission Control Relay connector in the IPM.
Using a 12-volt test light connected to ground, check the Transmission Control Relay
Output circuit in the Solenoid/Pressure Switch Assembly harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?All
Ye s®Go To 7
No®Repair the Transmission Control Relay Output circuit for an open
or high resistance.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
105
TRANSMISSION
P1781-OD PRESSURE SWITCH SENSE CIRCUIT ÐContinued