DTC P0796 or P0797
Diagnostic Instructions
DTC Descriptors
DTC P0796: Pressure Control Solenoid Valve 3
Stuck Off
DTC P0797: Pressure Control Solenoid
Valve 3 Stuck On
Circuit/System Description
The clutch pressure control (PC) solenoid 3 is part of
the control solenoid valve assembly which has no serviceable
components. PC solenoid 3 regulates transmission fluid
pressure to the R1/4-5-6 regulator valve which controls
pressure to the reverse and low clutch and the 4-5-6 clutch.
The transmission control module (TCM) calculates gear ratio
based on the RPM signals from the automatic transmission input
speed sensor (ISS) and the output speed sensor (OSS). The
TCM compares the expected transmission gear ratio to the calculated
gear ratio for each commanded gear.
Conditions for Running the DTC
P0796
• |
DTC P0101, P0102, P0103, P0106, P0107, P0108,
P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205,
P0206, P0207, P0208, P0300, P0301, P0302, P0303, P0304, P0305,
P0306, P0307, P0308, P0401, P042E, P0716, P0717, P0722, P0723, or
P182E is not set. |
• |
The engine speed is greater than 400 RPM for
5 seconds. |
• |
The transmission output speed is 650 RPM or
greater or the throttle position is 0.5 percent or
greater. |
• |
The ignition voltage is 9.0 volts or
greater. |
• |
The transmission fluid temperature (TFT) is
-7°C (19°F) or greater. |
• |
The high side driver (HSD) is enabled. |
• |
The throttle position signal is valid. |
P0797
• |
DTC P0101, P0102, P0103, P0106, P0107, P0108,
P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205,
P0206, P0207, P0208, P0300, P0301, P0302, P0303, P0304, P0305,
P0306, P0307, P0308, P0401, P042E, P0716, P0717, P0722, P0723, or
P182E is not set. |
• |
The engine speed is greater than 400 RPM for
5 seconds. |
• |
The transmission output speed is 650 RPM or
greater or the throttle position is 0.5 percent or
greater. |
• |
The throttle position signal is valid. |
• |
The ignition voltage is 9.0 volts or
greater. |
• |
The TFT is -7°C (19°F) or greater. |
• |
The transmission output shaft speed is
200 RPM or greater. |
Conditions for Setting the DTC
P0796
The TCM detects an incorrect on-coming clutch gear ratio
(incorrect gear ratio), or flare.
P0797
The TCM detects an incorrect off-going clutch gear ratio
(incorrect gear ratio), or shift tie-up.
Action Taken When the DTC Sets
P0796
• |
DTC P0796 is a Type A DTC. |
• |
The TCM commands maximum line pressure. |
• |
The TCM freezes transmission adaptive
functions. |
• |
The TCM inhibits TAP Up/TAP Down functions. |
• |
The TCM inhibits manual up, manual down shifts
with the shift selector. |
• |
The TCM limits the transmission to reverse and 3rd
gear. |
P0797
• |
DTC P0797 is a Type A DTC. |
• |
The TCM commands maximum line pressure. |
• |
The TCM freezes transmission adaptive
functions. |
• |
The TCM inhibits TAP Up/TAP Down functions. |
• |
The TCM inhibits manual up, manual down shifts
with the shift selector. |
• |
The TCM limits the transmission to reverse and 4th
gear. |
Conditions for Clearing the DIC/DTC
DTCs P0796 and P0797 are Type A DTCs.
Diagnostic Aids
Before performing a road test, configure and set-up the scan
tool for snapshot mode. This allows you to monitor, display, and
verify multiple transmission data parameters at one time, after the
road test.
Reference Information
Schematic Reference
Description and Operation
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Warning: Apply the handbrake and
chock the drive wheels before performing this procedure in order to
prevent bodily injury.
Note: If other DTCs are set,
diagnose those DTCs first.
- Engine ticking over in Park, with handbrake applied
and drive wheels chocked.
- Perform the
Transmission Fluid Level and Condition Check to verify correct
fluid level and condition.
- Monitor the Transmission Fluid Pressure Switch 5
parameter with a scan tool. Place the gear select lever in Park,
Reverse, and Neutral range. Verify the Transmission Fluid Pressure
Switch 5 parameter states are correct for Park, Reverse, and
Neutral. Refer to
Transmission Fluid Pressure Switch Logic .
- Place the gear select lever in Drive range. Command
the shift transmission with a scan tool through all forward ranges.
Verify the Transmission Fluid Pressure Switch 5 parameter
states are correct for all forward ranges. Refer to
Transmission Fluid Pressure Switch Logic .
- Engine ticking over in Park, verify with a scan tool
the Transmission ISS/OSS Supply Voltage test status parameter
displays OK.
- Engine ticking over in Park. Observe the Transmission
ISS parameter on the scan tool, while varying the engine speed. The
Transmission ISS parameter should vary with engine speed and not
drop out.
- Operate the vehicle at 16-32 km/h
(10-20 mph) while observing the Transmission OSS parameter on
the scan tool. The Transmission OSS parameter should vary with the
vehicle speed and not drop out.
Note: Perform a scan tool
snapshot, during the road test.
- Perform the
Road Test . Verify the transmission operation performs as
indicated in the road test instructions.
- Review the scan tool snapshot data. Verify the
following transmission data parameters display the correct values
for each gear range.
• |
Pressure Control Solenoid Valve 3 Pressure
Command |
• |
Transmission Fluid Pressure Switch 5 |
- After performing the above steps, verify that the DTC
does not reset by operating the vehicle within the Conditions for
Running the DTC. You may also operate the vehicle within the
conditions you observe from the Freeze Frame/Failure Records data.
If the vehicle passes the Circuit/System Verification procedure,
then STOP. Do not perform the Circuit/System Testing or Component
Testing as this may result in an unnecessary part replacement.
Refer to
Testing for Intermittent Conditions and Poor Connections .
Circuit/System Testing
Note: You must perform the
Circuit/System Verification first.
- Perform the
Line Pressure Check . Verify the transmission line pressures
are within the range specified in the Line PC Solenoid Valve
Pressure table. Refer to
Solenoid Valve Pressure .
- Ignition OFF, remove the Q8 control solenoid valve
assembly. Refer to
Control Solenoid Valve and Transmission Control Module Assembly
Replacement .
- Perform the
Control Solenoid Valve and Transmission Control Module Assembly
Solenoid Performance Test .
⇒ |
If the Q8 control solenoid valve body does not
pass the performance test, replace the Q8 control solenoid valve
assembly. |
- Inspect for the following conditions and
repair/replace as necessary.
DTCs
|
Component
|
Condition
|
P0796
P0797
|
Control Valve Body Assembly
|
4-5-6 Regulator Valve stuck/sticking - debris, binding, damaged
valve, or scored bore
|
P0796
|
Input Shaft Support
|
Input shaft tower seals damaged or leaking
|
P0796
P0797
|
Q8 Control Solenoid Valve Assembly
|
• |
Clutch Pressure Control Solenoid 3 |
• |
Valve body filter plate assembly cracked, blocked,
or damaged gasket seal |
|
P0796
|
4-5-6 Clutch Housing Assembly
|
4-5-6 Clutch Piston Assembly damaged/leaking
|
P0796
|
Transmission Cooling/Lubrication
|
• |
Restriction/leak in OAC (oil to air)
cooler/radiator |
• |
Restricted/leaking/kinked/damaged transmission oil
cooler lines |
• |
Restriction/leak in transmission fluid pump
assembly |
|
P0796
|
Torque Converter (w/Fluid Pump) Housing Assembly
|
• |
Fluid pump housing vanes/rotor/slide
damaged/scored |
• |
Fluid pump or torque converter overstressed due to
high temperature |
|
P0796
|
4-5-6 Reaction carrier hub assembly
|
4-5-6 reaction carrier Hub/Shaft - broken hub weld
|
P0796
|
Automatic Transmission Fluid Filter Assembly
|
Oil filter or filter seal loose or damaged
|
P0796
|
3-5-R and 4-5-6 Clutch Housing Assembly
|
4-5-6 Clutch Backing Plate Retaining Ring not seated/oriented,
causing clutch pack/piston over-travel
|
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|