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TPMS: Rotate Cadillac SRX tires, relearn sensors

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TPMS: Rotate Cadillac SRX tires, relearn sensors

SUBJECT VEHICLE: 2010-2012 Cadillac SRX.

RELEARN PROCEDURE? Yes.

SPECIAL TOOLS NEEDED? Yes, a TPMS sensor activation tool and a tire valve stem mounting tool.

The tire pressure monitoring system (TPMS) on the 2010-2012 Cadillac SRX uses the Body Control Module (BCM), Instrument Panel Cluster (IPC), four RF transmitting pressure sensors and the serial data circuit to perform the TPMS learn mode functions. NOTE: When the wheels have been rotated, or a tire pressure sensor has been replaced, retrain tire pressure sensors.

The sensor learn procedure must be performed after every tire rotation, BCM replacement, or sensor replacement. Once the TPMS learn mode has been enabled, each of the sensor unique identification (ID) codes can be learned into the BCM memory.

When a sensor ID has been learned, the BCM sounds a horn chirp verifying ID transmission has been received and learned. The BCM must learn the sensor IDs in the proper order to determine correct sensor location. The first learned ID is assigned to the left-front, the second to right-front, the third to right-rear and the fourth to left-rear.

Functions using pressure increase/decrease method

Each sensor takes a pressure measurement sample once every 30 seconds while in stationary mode. If the tire pressure increases or decreases by more than 1.2 psi from the last pressure measurement, another measurement will occur immediately to verify the change in pressure.

If a pressure change has occurred, the sensor transmits in learn mode. When the BCM receives a learn mode transmission while in TPMS learn mode, it will assign that sensor ID to the location on the vehicle relative to the order in which it was learned.

Learn mode cancellation

The learn mode will cancel if the ignition is cycled to OFF or if more than two minutes has elapsed for any sensor that has not been learned. If the learn mode is cancelled before the first sensor is learned, the original sensor IDs will be maintained. If the learn mode is canceled for any reason after the first sensor is learned, all IDs are erased from the BCM memory and if equipped, the Driver Information Center (DIC) will display dashes for tire pressures.

The BCM has the ability to detect malfunctions within the TPMS. Any malfunction detected will cause the DIC to illuminate continuously each time the ignition is turned ON until the malfunction is corrected.

Warning indicators

The tire pressure monitor indicator icon on the IPC will flash for one minute and then it will remain illuminated. When that happens the DIC will display the “SERVICE TIRE MONITOR SYSTEM” message if one or more of the tire pressure sensors or other system components has malfunctioned. “SERVICE TIRE MONITOR SYSTEM” will also be displayed if all of the sensors have not been programmed successfully. If warning indicators are still on, there is a problem in the TPMS. See the manufacturer’s service information, or call the company’s service help line.

Reset and relearn procedures

When the TPMS detects a significant loss or gain of tire pressure, the CHECK TIRE PRESSURE message is displayed on the DIC and the low tire pressure indicator is displayed on the IPC. Both the DIC message and IPC indicator can be cleared by adjusting the tire pressure to the recommended kPa/psi and driving the vehicle above 25 mph (40km/h) for at least two minutes.

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Tire pressure sensor relearn

WARNING: If not utilizing a scan tool to initiate the relearn procedure, stray signals from other TPMS-equipped vehicles just driving by can be inadvertently learned.

If any random horn chirps are heard from the vehicle while performing the learn procedure, most likely a stray sensor has been learned and the procedure will need to be canceled and repeated. Under these circumstances, performing the TPMS learn procedure away from other vehicles would be highly recommended.

In the event a particular sensor activation does not cause the horn to chirp, it may be necessary to rotate the wheel valve stem to a different position due to the sensor signal being blocked by another component.

Before proceeding with the steps below, verify the following:

•  no other sensor learn procedure is being performed simultaneously within close proximity;

•  tire pressures are not being adjusted on another TPMS-equipped vehicle within close proximity;

•  Park Brake Switch input parameters are functioning correctly.

1. Apply the parking brake (manual transmission only).

2. Turn ON the ignition, with the engine OFF.

3. Using a scan tool or the DIC, select Tire Pressure Sensor Relearn. A double horn chirp will sound and the left-front turn signal will be illuminated.

4. Starting with the left-front tire, learn the tire pressure using one of the following methods:

Method 1: Hold the antenna of the TPMS sensor activation tool against the tire sidewall close to the wheel rim, at the valve stem location, then press and release the activate button and wait for a horn chirp.

Method 2: Increase/decrease the tire pressure for eight to 10 seconds, then wait for a horn chirp. The horn chirp may occur before or up to 30 seconds after the eight to 10 second pressure increase/decrease time period has been reached.

5. After the horn chirp has sounded, repeat Step 4 for the remaining three sensors in the following order: right-front, right-rear, and left-rear.

6. After the left-rear sensor has been learned, a double horn chirp will sound indicating all sensors have been learned.

7. Turn OFF the ignition to exit the learn mode.

8. After the learn mode has been exited, adjust all tires to the recommended pressures.

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Demounting/mounting procedures

CAUTION: The tire should be demounted from the wheel using the tire changer manufacturer’s instructions. Use the following information to avoid damage during the demounting/mounting procedures.

NOTE: If vehicle’s tires are replaced with those not having a Transmit Power Control (TPC) Spec number, the TPMS may give an inaccurate low pressure warning. Non-TPC Spec tires may give a low pressure warning that is higher or lower than the proper warning level achieved by TPC Spec numbered tires.

NOTE: When the wheels have been rotated, or a tire pressure sensor has been replaced, retrain the tire pressure sensor. See “Reset and relearn procedures.”

CAUTION: Do not inject any tire liquid or aerosol tire sealant into tires, as this may cause a malfunction of the tire pressure sensors. If any tire sealant is noted upon tire demounting, replace the sensor. Also remove all residual liquid sealant from the inside of the tire and wheel surfaces.

To remove an old sensor, follow these steps.

1. Raise the vehicle on a suitable support. Remove the tire/wheel assembly from vehicle.

2. Demount the tire from the wheel following the tire changer manufacturer’s instructions.

3. Remove the TORX screw (1) from the tire pressure sensor (2) and pull it straight off the tire pressure valve stem (3). See Figure 1.

4. Remove the tire pressure valve stem by pulling it through the rim.

To install a new sensor, follow these steps.

NOTE: When servicing the tire pressure sensor always use a new tire pressure monitor (TPM) and a new TORX screw during installation.

1. Assemble the tire pressure sensor (2) to the valve stem and install the new TORX screw (3). TPM valves and TORX screws are one-time use only.

2. Apply tire soap to the rubber portion of the valve stem (1).

3. Using a tire valve stem mounting tool, pull the valve stem through in a direction parallel to the valve hole on the rim.

4. Mount the tire to the rim.

5. Install the tire on the wheel. Install the tire/wheel assembly on the vehicle. Retrain tire pressure sensor. See “Reset and relearn procedures.”    ■

Information for this column comes from Mitchell 1’s ”Tire Pressure Monitoring Systems Guide” for domestic and import vehicles, updated through 2012. Headquartered in Poway, Calif., Mitchell 1 has provided quality repair information solutions to the automotive industry for more than 80 years. For more information, visit www.mitchell1.com.

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