Escalade, Suburban 1500 & 2500, Tahoe, Yukon, Yukon XL 1500 & 2500 (2006-2007), Yukon Denali and Yukon Denali XL (2005-2006)

4.8L V8 VIN C Auto 5

Print

Trouble Code: P0722



Output Speed Sensor Circuit No Signal

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.If the condition is intermittent, connect the scan tool and select the speed sensor indicated by the code. If the signal is erratic, investigate and eliminate the following:

Intermittent wiring connection
 
Excessive vibration, such as driveline or engine torsionals
 
Irregular sensor gap, such as a loose sensor, a loose tone wheel or a damaged tone wheel
 
Inspect that the speed sensor wiring consists of twisted pairs at the rate of 12-16 twists per 300 mm (12 in). These twists must extend the entire length of the wiring harness to within at least 50 mm (2 in) of the speed sensor connector.
 

 

Trouble Code: P0723



Output Speed Sensor (OSS) Intermittent

Possible Causes:



Inspect the OSS, harness, connector and control solenoid (w/body and TCM) valve assembly pins for metallic debris and output shaft machined face for damage or misalignment. Proper torque of the OSS mounting bolt is critical to proper OSS operation. Use the J 35616 GM-approved terminal test kit for any test that requires probing the control solenoid (w/body and TCM) valve assembly harness connector or a component harness connector.
 

Trouble Code: P0724



Brake Switch Circuit High Voltage

Possible Causes:



Inspect the brake switch for proper mounting and operation.
 

Trouble Code: P0724



TCC Brake Switch Circuit High Voltage

Possible Causes:



Inspect the TCC brake switch for proper mounting and operation.
 
Inspect for ABS DTCs. A faulty ABS condition may contribute to setting DTC P0724.
 

Trouble Code: P0726



Engine Speed Sensor Circuit Performance

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.If the condition is intermittent, connect the scan tool and select the speed sensor indicated by the code. If the signal is erratic, investigate and eliminate the following:

Intermittent wiring connection
 
Excessive vibration, such as driveline or engine torsionals
 
Irregular sensor gap, such as a loose sensor, a loose tone wheel or a damaged tone wheel
 
Inspect that the speed sensor wiring consists of twisted pairs at the rate of 12-16 twists per 300 mm (12 in). These twists must extend the entire length of the wiring harness to within at least 50 mm (2 in) of the speed sensor connector.
 

 

Trouble Code: P0727



Engine Speed Sensor Circuit No Signal

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.If the condition is intermittent, connect the scan tool and select the speed sensor indicated by the code. If the signal is erratic, investigate and eliminate the following:

Intermittent wiring connection
 
Excessive vibration, such as driveline or engine torsionals
 
Irregular sensor gap, such as a loose sensor, a loose tone wheel or a damaged tone wheel
 
Inspect that the speed sensor wiring consists of twisted pairs at the rate of 12-16 twists per 300 mm (12 in). These twists must extend the entire length of the wiring harness to within at least 50 mm (2 in) of the speed sensor connector.
 

 

Trouble Code: P0729



Incorrect 6th Gear Ratio

Possible Causes:



Incorrect ratio codes typically indicate mechanical conditions with specific clutches, such as 2-6 clutch and 3-5-6-REVERSE clutch for 6th range.
 
Incorrect ratio code could indicate a hydraulically failed solenoid. Observe DTC information for the specific solenoid.
 
Clutch test mode can be used to measure stall speed. Observe turbine speed signal. If the turbine speed signal does not return to zero or rises during the stall test, a leak or obstruction in a specific clutch apply circuit could be present.
 
You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P0730



Incorrect Gear Ratio

Possible Causes:



A false or incorrect AT OSS or AT ISS signal can set DTC P0730.
 
DTC P0894 detects an incorrect gear ratio in fourth gear with the torque converter clutch (TCC) applied.
 
Inspect for any improperly installed aftermarket equipment.
 
Sticking or contamination of shift valves may cause intermittent incorrect gear ratios.
 
Refer to Shift Solenoid Valve State and Gear Ratio .
 
DTC P0730 defaults to an elevated line pressure which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
 

Trouble Code: P0731



Incorrect 1st Gear Ratio

Possible Causes:



Incorrect ratio codes typically indicate mechanical conditions with specific clutches, such as 1-2-3-4 clutch or low and reverse clutch for 1st range.
 
Incorrect ratio code could indicate a hydraulically failed solenoid. Observe DTC information for the specific solenoid.
 
Clutch test mode can be used to measure stall speed. Observe turbine speed signal. If the turbine speed signal does not return to zero or rises during the stall test, a leak or obstruction in a specific clutch apply circuit could be present.
 
You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P0732



Incorrect 2nd Gear Ratio

Possible Causes:



Incorrect ratio codes typically indicate mechanical conditions with specific clutches, such as 1-2-3-4 clutch and 2-6 clutch for 2nd range.
 
Incorrect ratio code could indicate a hydraulically failed solenoid. Observe DTC information for specific solenoid.
 
Clutch test mode can be used to measure stall speed. Observe turbine speed signal. If the turbine speed signal does not return to zero or rises during the stall test, a leak or obstruction in a specific clutch apply circuit could be present.
 
You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P0733



Incorrect 3rd Gear Ratio

Possible Causes:



Incorrect ratio codes typically indicate mechanical conditions with specific clutches, such as 1-2-3-4 clutch and 3-5-Reverse clutch, for 3rd range.
 
Incorrect ratio code could indicate a hydraulically failed solenoid. Observe DTC information for specific solenoid.
 
Clutch test mode can be used to measure stall speed. Observe turbine speed signal. If the turbine speed signal does not return to zero or rises during the stall test, a leak or obstruction in a specific clutch apply circuit could be present.
 
You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P0734



Incorrect 4th Gear Ratio

Possible Causes:



Incorrect ratio codes typically indicate mechanical conditions with specific clutches, such as 1-2-3-4 clutch and 4-5-6 clutch, for 4th range.
 
Incorrect ratio code could indicate a hydraulically failed solenoid. Observe DTC information for specific solenoid.
 
Clutch test mode can be used to measure stall speed. Observe turbine speed signal. If the turbine speed signal does not return to zero or rises during the stall test, a leak or obstruction in a specific clutch apply circuit could be present.
 
You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P0735



Incorrect 5th Gear Ratio

Possible Causes:



Incorrect ratio codes typically indicate mechanical conditions with specific clutches, such as 4-5-6 clutch and 3-5-Reverse clutch, for 5th range.
 
Incorrect ratio code could indicate a hydraulically failed solenoid. Observe DTC information for specific solenoid.
 
Clutch test mode can be used to measure stall speed. Observe turbine speed signal. If the turbine speed signal does not return to zero or rises during the stall test, a leak or obstruction in a specific clutch apply circuit could be present.
 
You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P0736



Incorrect Reverse Ratio

Possible Causes:



Incorrect ratio codes typically indicate mechanical conditions with specific clutches, such as 3-5-Reverse clutch and low and reverse clutch for REVERSE range.
 
Incorrect ratio code could indicate a hydraulically failed solenoid. Observe DTC information for specific solenoid.
 
Clutch test mode can be used to measure stall speed. Observe turbine speed signal. If the turbine speed signal does not return to zero or rises during the stall test, a leak or obstruction in a specific clutch apply circuit could be present.
 
You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P0740



Torque Converter Clutch (TCC) Enable Solenoid Control Circuit

Possible Causes:



With the TCC engaged, the TCC slip speed should be -20 to +50 RPM.
 

Trouble Code: P0741



Torque Converter Clutch (TCC) System - Stuck Off

Possible Causes:



Residue or contamination may cause TCC hydraulic valves to stick intermittently.
 
DTC P0741 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
 

Trouble Code: P0741



Torque Converter Clutch (TCC) System - Stuck Off

Possible Causes:



Contamination may cause the TCC apply valve to stick in the valve body.
 
There may be internal damage in the torque converter causing the no TCC apply.
 

Trouble Code: P0741



Torque Converter Clutch (TCC) - Stuck Off

Possible Causes:



When attempting to set transmission performance DTCs, it may be helpful to observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. Ensure the transmission fluid level is correct and there are no leaks.
 

Trouble Code: P0741



Torque Converter Clutch (TCC) System - Stuck Off

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P0742



Torque Converter Clutch (TCC) System - Stuck On

Possible Causes:



If the TCC is mechanically stuck ON with the parking brake applied and any gear range selected, the TCC fluid mechanically applies the TCC. TCC fluid mechanically applying the TCC can cause an engine stall.
 
DTC P0742 defaults to an elevated line pressure which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
 
A stuck throttle position sensor may set a DTC P0742.
 

Trouble Code: P0742



Torque Converter Clutch (TCC) System - Stuck On

Possible Causes:

The TCC fluid hydraulically applies the TCC, possibly causing an engine stall, under the following conditions:



The TCC is hydraulically stuck ON
 
The parking brake is applied
 
Any gear range is selected
 

Trouble Code: P0742



Torque Converter Clutch (TCC) - Stuck On

Possible Causes:



When attempting to set transmission performance DTCs, it may be helpful to observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. Ensure the transmission fluid level is correct and there are no leaks.
 

Trouble Code: P0742



Torque Converter Clutch (TCC) System - Stuck On

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P0748



Pressure Control (PC) Solenoid Control Circuit

Possible Causes:



Inspect the PC solenoid wiring for aftermarket products designed to alter transmission line pressure.
 
DTC P0748 defaults to an elevated line pressure condition which may result in partial torque converter clutch (TCC) apply. This may produce an idle surge that could stall the engine.
 

Trouble Code: P0748



Pressure Control (PC) Solenoid Control Circuit

Possible Causes:



DTC P0748 may set under low voltage conditions caused by high electrical system demands.
 

Trouble Code: P0751



1-2 Shift Solenoid Valve Performance - No First or Fourth Gear

Possible Causes:



Verify that the transmission meets the specifications in the Shift Speed table. Refer to Shift Speed .
 
Other internal transmission failures may cause incorrect gear ratios to occur. Refer to Shift Solenoid Valve State and Gear Ratio .
 
DTC P0751 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
 

Trouble Code: P0751



1-2 Shift Solenoid Valve Performance - No First or Fourth Gear

Possible Causes:



Verify that the transmission meets the specifications in the Shift Speed .
 
Other internal transmission failures may cause more than one shift to occur.
 
Refer to the Shift Solenoid Valve State and Gear Ratio .
 

Trouble Code: P0751



Shift Solenoid (SS) 1 Valve Performance - Stuck Off

Possible Causes:



When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. Ensure the transmission fluid level is correct and there are no leaks.
 

Trouble Code: P0751



Shift Solenoid (SS) 1 Valve Performance - Stuck Off

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.This DTC may indicate that SS1 is mechanically defective or the shift valve is stuck in the destroked state.When DTC P0751 and P0843 are set in combination, this may indicate an open circuit condition is present at the pressure switch circuit or the shift valve is stuck in the destroked position.
 

Trouble Code: P0752



1-2 Shift Solenoid Valve Performance - No Second or Third Gear

Possible Causes:



Verify that the transmission meets the specifications in the Shift Speed table. Refer to Shift Speed .
 
Other internal transmission failures may cause incorrect gear ratios to occur. Refer to Shift Solenoid Valve State and Gear Ratio .
 
DTC P0752 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
 

Trouble Code: P0752



1-2 Shift Solenoid Valve Performance - No Second or Third Gear

Possible Causes:



Verify that the transmission meets the specifications in the Shift Speed .
 
Other internal transmission failures may cause more than one shift to occur.
 
Refer to the Shift Solenoid Valve State and Gear Ratio .
 

Trouble Code: P0752



Shift Solenoid (SS) 1 Valve Performance - Stuck On

Possible Causes:



When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. Ensure the transmission fluid level is correct and there are no leaks.
 

Trouble Code: P0752



Shift Solenoid (SS) 1 Valve Performance - Stuck On

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.This DTC may indicate that SS1 is mechanically defective or the shift valve is stuck in the stroked state.When DTC P0752 and P0842 are set in combination, this may indicate a short to ground is present at the pressure switch circuit or the shift valve is stuck in the stroked state.
 

Trouble Code: P0753



1-2 Shift Solenoid Control Circuit

Possible Causes:



An open ignition feed on the Off/Run/Crank voltage circuit can cause multiple DTCs to set. Refer to Shift Solenoid Valve State and Gear Ratio .
 
DTC P0753 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
 

Trouble Code: P0753



1-2 Shift Solenoid Control Circuit

Possible Causes:



Refer to the Shift Solenoid Valve State and Gear Ratio .
 

Trouble Code: P0756



2-3 Shift Solenoid Valve Performance - No First or Second Gear

Possible Causes:



Verify that the transmission meets the specifications in the Shift Speed table. Refer to Shift Speed .
 
Other internal transmission failures may cause incorrect gear ratios to occur.
 
The customer may have concern of an engine over-rev condition or neutral condition in 4th gear. Refer to Shift Solenoid Valve State and Gear Ratio .
 
DTC P0756 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
 

Trouble Code: P0756



2-3 Shift Solenoid Valve Performance - No First or Second Gear

Possible Causes:



Verify that the transmission meets the specifications in the Shift Speed .
 
Other internal transmission failures may cause more than one shift to occur.
 
Refer to the Shift Solenoid Valve State and Gear Ratio .
 

Trouble Code: P0756



Shift Solenoid (SS) 2 Valve Performance - Stuck Off

Possible Causes:



When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. Ensure the transmission fluid level is correct and there are no leaks.
 

Trouble Code: P0756



Shift Solenoid (SS) 2 Valve Performance - Stuck Off

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.This DTC may indicate that SS2 is mechanically defective or the shift valve is stuck in the destroked state.When DTC P0756 and P0848 are set in combination, this may indicate an open circuit condition is present at the pressure switch circuit or the shift valve is stuck in the destroked position.
 

Trouble Code: P0757



2-3 Shift Solenoid Valve Performance - No Third or Fourth Gear

Possible Causes:



Verify that the transmission meets the specifications in the Shift Speed table. Refer to Shift Speed .
 
Other internal transmission failures may cause incorrect gear ratios to occur in 3rd gear.
 
The customer may have concern of an engine over-rev condition or neutral condition in 4th gear. Refer to Shift Solenoid Valve State and Gear Ratio .
 
DTC P0757 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
 

 
label.common.footer.alt.autozoneLogo