Question about GMC TPMS.

[lmorris]

I purchased a 2011 GMC Terrain SLE. It has the TMPS light that proves out in the cluster and stays off. Funny thing is there are no sensors in the wheels. Everything I can find about the system states there should be sensors in the wheels. Nothing states that the system may be optional on this vehicle. Does anyone know why this is? The VIN is 2CTFLTEC1B6264655. Thanks.

[8WA Sman]

According to my info I am not sure it has TPMS but I can find out for sure tomorrow.  

[Bruce Amacker]

IIRC, some systems don't use TP sensors but rather depend on the ABS sensors- if the tire is low, revs per mile speed up triggering a code. The system learns the revs for each wheel over time, rotating the tires screws this up sometimes requiring pushing the reset button.

 

Edit:  Alldata shows it has sensors.

 

2011 GMC Truck Terrain AWD L4-2.4L

Vehicle » A L L Diagnostic Trouble Codes ( DTC ) » Testing and Inspection » C Code Charts » C0755

• C0755

DTC C0750, C0755, C0760, or C0765

Diagnostic Instructions
 

• Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection\Initial Inspection and Diagnostic Overview\Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis (See: Testing and Inspection\Initial Inspection and Diagnostic Overview\Strategy Based Diagnosis) for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions (See: Testing and Inspection\Initial Inspection and Diagnostic Overview\Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC C0750 03

• Left Front Tire Pressure Sensor Low Voltage

DTC C0750 29

• Left Front Tire Pressure Sensor Too Few Pulses

DTC C0750 39

• Left Front Tire Pressure Sensor Internal Malfunction

DTC C0755 03

• Right Front Tire Pressure Sensor Low Voltage

DTC C0755 29

• Right Front Tire Pressure Sensor Too Few Pulses

DTC C0755 39

• Right Front Tire Pressure Sensor Internal Malfunction

DTC C0760 03

• Left Rear Tire Pressure Sensor Low Voltage

DTC C0760 29

• Left Rear Tire Pressure Sensor Too Few Pulses

DTC C0760 39

• Left Rear Tire Pressure Sensor Internal Malfunction

DTC C0765 03

• Right Rear Tire Pressure Sensor Low Voltage

DTC C0765 29

• Right Rear Tire Pressure Sensor Too Few Pulses

DTC C0765 39

• Right Rear Tire Pressure Sensor Internal Malfunction

Circuit/System Description

The tire pressure monitor (TPM) system has a radio frequency (RF) transmitting pressure sensor in each wheel/tire assembly. As vehicle speed increases, centrifugal force closes the sensors internal roll switch, which puts the sensor into Rolling mode. The body control module (BCM) receives and translates the data contained in the tire pressure sensor RF transmissions into sensor presence, sensor mode, and tire pressure. Once vehicle speed is greater than 40km/h (25 mph), the BCM waits for the first sensor to go into Rolling mode, then checks if all sensors have gone into Rolling mode. If one or more sensors do not go into these modes, or do not transmit at all, the BCM will set DTC C0750, C0755, C0760, or C0765 respectively.

Conditions for Running the DTC

Vehicle speed is greater than 40 km/h (25 mph).

Conditions for Setting the DTC
 

• A sensor does not transmit for 18 minutes.
• A sensor low battery condition.

Action Taken When the DTC Sets
 

• The tire pressure monitor indicator icon on the instrument panel cluster (IPC) flashes for 1 minute and then remains illuminated after the ignition switch is cycled ON and the IPC bulb check is complete.
• If equipped, the driver information center (DIC) displays the suspect tire pressure as dashes.
• If equipped, the DIC displays a service tire monitor type message.

Conditions for Clearing the DTC
 

• A current DTC will clear when the malfunction is no longer present and 1 ignition cycle occurs.
• The BCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids
 

• Some aftermarket wheel valve stem holes are located further from the wheel rim than original equipment wheels. When using the TPM special tool to activate a sensor, ensure the tool antenna is no further than 15 cm (6 in) from the sensor and is aiming upward.
• Aftermarket wheel valve stem locations can cause a sensor to not function correctly.
• A sensor may have been damaged due to a previous wheel/tire service or flat tire event.
• The use of other than GM approved tire sealants can obstruct the sensor pressure sensing port and cause inaccurate tire pressure readings. If this condition is verified, remove the sealer from the tire and replace the sensor. Refer to Tire Pressure Indicator Sensor Replacement (See: Instrument Panel, Gauges and Warning Indicators\Tire Pressure Sensor\Service and Repair).
• Occasionally sensor transmissions are not received by the BCM due to vehicle level RF interference from items such as but not limited to aftermarket ignition systems, DVD players, CB radios, or metallic type window tinting.
• The sensor activation procedure may have to be repeated up to 3 times before determining a sensor is malfunctioning. In the event a particular sensor information is displayed on the special tool upon activation but the horn does not chirp, it may be necessary to rotate the wheel valve stem to a different position due to the RF signal is being blocked by another component.
• Occasionally sensors can become mislocated due to previous tire rotations where the sensor learn procedure was not performed or stray sensor transmissions have been received from other vehicles. Always learn the sensors to ensure the DTC set is for that actual physical corner of the vehicle. Refer to Tire Pressure Indicator Sensor Learn (See: Instrument Panel, Gauges and Warning Indicators\Tire Pressure Sensor\Testing and Inspection).
• A sensor low battery condition will set a sensor DTC but will not illuminate the low tire pressure indicator or display a message on the DIC, if equipped. The sensor battery condition can be verified in the scan tool BCM data list. If a sensor low battery condition is indicated on the scan tool, the sensor will need to be replaced. Refer to Tire Pressure Indicator Sensor Replacement (See: Instrument Panel, Gauges and Warning Indicators\Tire Pressure Sensor\Service and Repair).

Reference Information
Description and Operation

Tire Pressure Monitor Description and Operation (See: Instrument Panel, Gauges and Warning Indicators\Tire Monitoring System\Description and Operation)
Electrical Information Reference
 

• Circuit Testing (See: Testing and Inspection\Component Tests and General Diagnostics\General Electrical Diagnostic Procedures\Circuit Testing\Circuit Testing)
• Connector Repairs (See: Testing and Inspection\Component Tests and General Diagnostics\General Electrical Diagnostic Procedures\Connector Repairs\Connector Repairs)
• Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection\Component Tests and General Diagnostics\General Electrical Diagnostic Procedures\Circuit Testing\Testing for Intermittent Conditions and Poor Connections)
• Wiring Repairs (See: Testing and Inspection\Component Tests and General Diagnostics\General Electrical Diagnostic Procedures\Wiring Repairs\Wiring Repairs)

Scan Tool Reference

Control Module References (See: Testing and Inspection\Programming and Relearning) for scan tool information
Special Tools

EL-46079/J-46079 Tire Pressure Monitor Diagnostic Tool

Circuit/System Verification
 

1. Using the EL-46079/J-46079 , activate each tire pressure sensor and record each sensors transmission data and physical location. Verify EL-46079/J-46079 displays the 8-digit ID number, accurate tire pressure +/- 27.6 kPa (4 psi), Learn Mode, and at least a 1/4 graph signal strength displayed.

¤	If any of the parameters listed above are not displayed, replace the suspect tire pressure sensor.

2. With the scan tool, verify tire pressure sensors ID and locations displayed on the scan tool match the IDs and locations recorded from the special tool.

¤	If the IDs and locations do not match, perform the Tire Pressure Indicator Sensor Learn (See: Instrument Panel, Gauges and Warning Indicators\Tire Pressure Sensor\Testing and Inspection).

3. Enable the TPM learn mode. Use the EL-46079/J-46079 in simulate mode to learn 4 simulated sensor transmissions into the BCM. Verify that all 4 simulated sensor locations, IDs, and tire pressures displayed on the TPM special tool match the corresponding scan tool parameters displayed.

¤	If the scan tool does not match, replace the K9 BCM.

4. Test drive the vehicle above 40 km/h (25 mph) for greater than 2 minutes. With the scan tool, observe the suspect Pressure Sensor Mode data parameter. Verify the sensor mode changes to Rolling.

¤	If the Pressure Sensor Mode does not change, replace the suspect tire pressure sensor.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
 

• Tire Pressure Indicator Sensor Replacement (See: Instrument Panel, Gauges and Warning Indicators\Tire Pressure Sensor\Service and Repair)
• Tire Pressure Indicator Sensor Learn (See: Instrument Panel, Gauges and Warning Indicators\Tire Pressure Sensor\Testing and Inspection)
• Control Module References (See: Testing and Inspection\Programming and Relearning) for BCM replacement, setup and programming.

[lmorris]

So I finally got around to getting this thing into work and hooked up our Snap on scanner. I found all the TPMS pids and they all show as being active with one Tire showing low pressure. But still no light on. So far I've had no low pressure issues with it but.......well you know how it goes....

This is baffling, it makes no sense as to why there is no light on. I don't want to spend the money on sensors if for some reason the system is disabled. Seems like a potential waste of money. I was tempted to use the wheels off my Focus put beside the GMC and see what happens, but with my luck it would learn those sensors and then turn the light on after....