P0752

DTC P0751 or P0752

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0751
- Shift Solenoid (SS) 1 Valve Performance - Stuck Off

DTC P0752
- Shift Solenoid (SS) 1 Valve Performance - Stuck On

Circuit/System Description

Shift solenoid valve 1 is part of the control solenoid valve assembly, which has no serviceable components. The solenoid operates by the transmission control module (TCM) turning the low side driver ON or OFF. When the shift solenoid valve 1 is commanded OFF, the plunger forces the metering ball against the actuator feed limit seat, blocking the flow and any existing pressure is exhausted through the exhaust port. When the shift solenoid valve 1 is commanded ON, the internal plunger moves, allowing the metering valve to move away from the actuator feed limit seat and against the exhaust seat, creating signal fluid pressure. The signal fluid pressure acts against the clutch select valve 2 to overcome the valve spring force, moving the valve to the apply position. Fluid pressure from the R1/4-5-6 regulator valve flows through clutch select valve 2 and is directed to either the low and reverse clutch or the 4-5-6 clutch, depending on the position of clutch select valve 2.

Conditions for Running the DTC

* DTC P0101, P0102, P0103, P0106, P0107, P0108, P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0401, P042E, P0716, P0717, P0722, P0723, or P182E is not set.

* Ignition voltage is greater than 8 V.

* Engine speed is 400-7,500 RPM for 5 s.

* Throttle position signal is valid.

* Engine torque signal is valid.

* High side driver is enabled.

* Output shaft speed is 36 RPM or greater, or the throttle position is 0.5 % or greater.

* Transmission fluid temperature is -6.6°C (20°F) or greater.

Conditions for Setting the DTC

P0751

* Commanded gear is 1st.

* TCM detects gear ratio 1.34-1.48.

* Gear slip is 400 RPM or greater for 2 s.

* Above conditions have to occur 8 times.

P0752

* Commanded gear is 3rd

* Transmission has achieved 1st or 2nd.

* Gear slip is 400 RPM or greater for 3 s.

* TCM commands 4th gear if above conditions exist and detects a gear ratio of 4.26-4.71 for 3 s.

* The conditions listed above have to occur 5 times.

Action Taken When the DTC Sets

P0751

* DTC P0751 is a Type B DTC.

* TCM inhibits 1st gear.

* TCM inhibits neutral idle.

P0752

* DTC P0752 is a Type A DTC.

* TCM freezes transmission adaptive functions.

* TCM commands maximum line pressure.

* TCM inhibits Tap Up/Down function.

* TCM inhibits manual shifting of forward gears.

* TCM commands second gear if output speed is less than 1,350 RPM, or neutral if output speed is 1,350 RPM or greater.

* TCM inhibits neutral idle.

Conditions for Clearing the DTC

* DTC P0751 is a Type B DTC.

* DTC P0752 is a Type A DTC.

Diagnostic Aids

Before performing a road test, configure and setup the scan tool for snapshot mode. This allows you to display, monitor, and verify multiple transmission data parameters at one time, after the road test.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics Electrical Diagrams

Connector End View Reference

* Component Connector End Views A/C Compressor Clutch

* Inline Harness Connector End Views X100

Description and Operation

* Transmission General Description Transmission General Description

* Transmission Component and System Description Transmission Component and System Description

* Electronic Component Description Electronic Component Description

* Drive Range, First Gear Drive Range, First Gear

* Drive Range, Third Gear Drive Range, Third Gear

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

Note: If other DTCs are set, diagnose those DTCs first.

1. Engine idling at the normal operating temperature, gear selector in the Park position, parking brake applied, and drive wheels chocked.

2. Verify the transmission fluid level and condition is correct. Refer to Transmission Fluid Level and Condition Check Transmission Fluid Level and Condition Check.

• If the transmission fluid level and condition is not correct
Repair as necessary

• If the transmission fluid level and condition is correct

3. From a stop, accelerate to 72 km/h (45 mph) with the scan tool Calculated Throttle Position greater than 15 %. Perform this test 8 times.

4. Verify DTC P0751 or P0752 did not set.

• If DTC P0751 or P0752 set

Refer to Circuit/System Testing.

• If DTC P0751 or P0752 did not set

5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

6. Verify the DTC does not set.

• If the DTC sets
Refer to Circuit/System Testing.

• If the DTC does not set

7. All OK.

Circuit/System Testing

1. Engine idling at the normal operating temperature.

2. Verify the transmission line pressures are within the specified range. Refer to Line Pressure Check Line Pressure Check and Solenoid Valve Pressure Solenoid Valve Pressure.

• If the pressures are not within range
Refer to Fluid Pressure High or Low Fluid Pressure High or Low.

• If the pressures are within range

3. Ignition OFF, remove the Q8 Control Solenoid Valve Assembly.

4. Verify the pressure changes for all solenoids when performing the solenoid test. Refer to Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test.

• If the pressure does not change
Replace the Q8 Control Solenoid Valve Assembly.

• If the pressure changes

5. Verify the mechanical conditions listed below do not exist. Repair or replace as necessary.

P0751 - Upper Control Valve Body

* Clutch select valve 2 bore plug undersized causing a leak - plug should be a valve fit in the bore.

* Check ball #2 - missing, damaged or malformed, or damage to the seat causing leakage.

P0751 or P0752 - Upper Control Valve Body

Clutch select valve 2 stuck from debris, sediment, binding, or a scored bore.

P0751 or P0752 - Channel Plate and Spacer Plate

Oil channels or orifices blocked by debris.

P0751 - Lower Control Valve Body

* Shift solenoid 1 - not pressurizing, stuck OFF or leaking.

* Shift solenoid 1 - not exhausting, stuck ON.

P0751 or P0752 - Q8 Control Solenoid Valve Assembly

* Shift solenoid valve 1 stuck OFF or leaking.

* Shift solenoid valve 1 stuck ON.

* Valve body filter plate assembly cracked, blocked, or damaged gasket seal.

* Pressure control solenoid valve 3 stuck ON, stuck OFF, or leaking. Low and Reverse, and 4-5-6 regulator valve stuck or sticking from debris, sediment, binding or scored bore.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repairs.

* Perform the Reset Transmission Adapts Reset Procedure following all transmission repairs.

* Control Module References Control Module References for control solenoid valve assembly replacement, programming, and setup.