Well once those valve stem schrader valves are removed they need to be replaced as that damages them.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
You may notice that the Drivers Information Center (DIC) will list all 4 of the tires pressures at 0 PSI after performing a tire pressure sensor learn procedure. You may also notice that the Passengers Door Module (PDM) will read the correct learn value of the tires.
Anytime a Tire Pressure Sensor learn procedure is performed, the vehicle must be driven at highway speeds for 5 minutes to update the tire pressure values in the Drivers Information Center.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
J-46079 Tire Pressure Monitor Diagnostic Tool.
TPM Learn Mode Description
The tire pressure monitor (TPM) system uses the passenger door module (PDM), body control module (BCM), exterior lamp switch, park brake switch, 4 radio frequency (RF) transmitting pressure sensors, and the serial data circuit to perform the TPM learn mode functions. The sensor learn procedure must be performed after the PDM is replaced, a sensor is replaced, or a tire rotation. Once the TPM learn mode has been enabled, each of the sensors unique identification (Id) codes can be learned into the PDM's memory. When a sensor's Id has been learned, the PDM sends a serial data message to the BCM to sound a horn chirp. This verifies the sensor has transmitted it's Id and the PDM has received and learned it. The PDM must learn the sensors Id codes in the proper sequence in order to determine sensor location. The first learned Id is assigned to left front, the second to right front, the third to right rear and fourth to left rear.
Sensor Function Using the Pressure Increase/Decrease method
Each sensor takes a pressure measurement sample once every 20 seconds while in stationary mode. If the tire pressure increases, or decreases by more than 11 kPa (1.6 psi) from the last pressure measurement, another measurement will occur immediately to verify the change in pressure. If a pressure change has indeed occurred, the sensor transmits re-measure mode transmission. When the PDM receives a re-measure mode transmission while in TPM learn mode, it will assign that sensor Id to the location on the vehicle relative to the order in which it was learned.
Sensor Functions using J-46079
Each sensor has an internal low frequency (LF) coil. When J-46079 is used in activate mode it produces an LF transmission that activates the sensor. The sensor responds to an LF activation by transmitting in learn mode. When the PDM receives a learn mode transmission while in TPM learn mode, it will assign that sensor's Id to the location on the vehicle relative to the order in which it was learned.
TPM Learn Mode Cancellation
The PDM will cancel the learn mode if more then 2 minutes have passed and no sensors have been learned, or if the PDM has been in learn mode for more than 5 minutes. If the learn mode is canceled before any sensor has been learned, the PDM will remember all current sensor Ids and their locations. As soon as the fist sensor Id code is learned, all other Ids are erased from the PDM's memory.
Important: Before proceeding with the steps below, verify the following:
Caution: Over inflating tires may cause personal injury or damage to the tires and wheels. When increasing tire pressure do not exceed the maximum inflation pressure as noted on the tire sidewall.
Important: If a horn chirp does not sound after 35 seconds for any of the 4 sensors, turn the ignition OFF to exit the learn mode and repeat the procedure from step 1.
Let me know if this helps ok. You will need a Tech 2 scan tool to do this I believe.
TPM System Enable
The service replacement PDM/Switch assembly comes with the TPM system disabled to allow the same part number PDM to be used in both TPM and non TPM equipped vehicles. Once the TPM option is enabled in the PDM, it can not be disabled. Before proceeding with the steps below ensure the vehicle is TPM equipped (UJ6), refer to Label - Service Parts ID in General Information.
The Tire Pressure Monitor (TPM) system uses radio and sensor technology to check tire pressure levels. If your vehicle has this feature, sensors are mounted on each tire and wheel assembly, except the spare tire. The TPM sensors transmit tire pressure readings to a receiver located in the vehicle.
When a low tire pressure condition is detected, the TPM system will display the CHECK TIRE PRESSURE warning message on the Driver Information Center (DIC); and at the same time illuminate the low tire pressure warning symbol. For additional information and details about the DIC operation and displays see DIC Operation and Displays and DIC Warnings and Messages .
When the tire pressure monitoring system warning light is lit, one or more of your tires is significantly under-inflated. You should stop and check your tires as soon as possible, and inflate them to the proper pressure as indicated on the vehicle's tire information placard.
Driving on a significantly under-inflated tire causes the tire to overheat and can lead to tire failure. Under-inflation also reduces fuel efficiency and tire tread life, and may affect the vehicle's handling and stopping ability. Each tire, including the spare, should be checked monthly when cold and set to the recommended inflation pressure as specified in the vehicle placard and owner's manual.
The Certification/Tire label or the Tire and Loading Information label (tire information placard) shows the size of your vehicle's original tires and the correct inflation pressure for your vehicle's tires when they are cold. See Inflation - Tire Pressure . For the location of the tire and loading information label, see Loading Your Vehicle .
Your vehicle's TPM system can alert you about a low tire pressure condition but it does not replace normal tire maintenance. See Tire Inspection and Rotation and Tires .
Notice: Do not use a tire sealant if your vehicle has Tire Pressure Monitors. The liquid sealant can damage the tire pressure monitor sensors.
Each TPM sensor has a unique identification code. Any time you rotate your vehicle's tires or replace one or more of the TPM sensors, the identification codes will need to be matched to the new tire/wheel position. Each tire/wheel position is matched to a sensor, by increasing or decreasing the tire's air pressure. The sensors are matched to the tire/wheel positions in the following order: left front (LF); right front (RF); right rear (RR) and left rear (LR).
You will have one minute to match the first tire/wheel position, and five minutes overall to match all four tire/wheel positions. If it takes longer than one minute, to match the first tire and wheel, or more than five minutes to match all four tire and wheel positions the matching process stops and you will need to start over.
The TPM sensor matching process is outlined below:
The spare tire does not have a TPM sensor. If you replace one of the road tires with the spare, the CHECK TIRE PRESSURE message will be displayed on the DIC screen. This message should go off once you re-install the road tire containing the TPM sensor. The SVC TIRE MONITOR message is displayed when the TPM system is malfunctioning. One or more missing or inoperable TPM sensors will cause the service tire monitor message to be displayed. See your dealer for service.
The TPM system operates on a radio frequency subject to Federal Communications Commission (FCC) Rules and with Industry and Science Canada.
This device complies with Part 15 of the FCC Rules and with RSS-210 of Industry and Science Canada. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received including interference that may cause undesired operation of the device.
Changes or modifications to this system by other than an authorized service facility could void authorization to use this equipment.