2005 grand Cherokee service tire pressure system
I found this on another site, it may help to understand what is happening, I also saw that there is a problem with the valve stems cracking since they're made out of aluminum and causing that problem. Here's the explanation provided on another site:
RodneyJ Answered 6 years ago
If a customer with a 2005 or later DaimlerChrysler vehicle equipped with Tire Pressure Monitoring (TPM) is concerned that the TPM lamp is on continuously, please be sure to inform the customer that the system is in place to warn of a low tire pressure situation, and a system diagnosis may not be required. The customer should be aware of the following: The Tire Pressure Monitoring (TPM) System will warn the driver of a low tire pressure based on the vehicle recommended cold placard pressure (the placard is located on the drivers side B-pillar).
The tire pressure will vary with temperature by about 6.9 kPa (1 psi) for every 6.5 Degrees C (12 Degrees F). This means that when the outside temperature decreases, the tire pressure will decrease - the customer should adjust his tire pressure for this decrease in pressure - please refer the customer to his vehicle owner's manual for information on how to properly inflate his vehicle's tires. The tire pressure will also increase as the vehicle is driven - this is normal and there should be no adjustment for this increased pressure.
The TPM System will warn the driver of a low tire pressure if the tire pressure falls below the low pressure warning threshold for any reason, including low temperature effects.
The TPM System will continue to warn the driver of low tire pressure as long as the condition exists, and will not turn off until the tire pressure is at or above recommended cold placard pressure. Once the low tire pressure warning has been illuminated, the tire pressure must be increased to the recommended cold placard pressure in order for the TPM warning lamp to be turned off. The system will automatically update and the TPM warning lamp will extinguish once the updated tire pressures have been received. The vehicle may need to be driven for up to 10 minutes above 25 kph (15 mph) to receive this information.
A 2006 300 has a recommended cold (parked for more than 3 hours) placard of 207 kPa (30 psi).
If the ambient temperature is 18 Degrees C (65 Degrees F) and the measured tire pressure is 186 kPa (27 psi) the TPM lamp will be OFF.
IF NOTHING IS DONE TO THE AIR PRESSURE IN THE TIRES and the ambient temperature drops to 20 Degrees F (-7 Degrees C) while the vehicle is parked, the approximate tire pressure will be 157 kPa (23 psi) and the TPM lamp will be ON.
IF THE VEHICLE IS DRIVEN TO REACH NORMAL OPERATING TEMPERATURE
WITHOUT ADJUSTING THE AIR PRESSURE and the ambient temperature stays at -7 Degrees C (20 Degrees F), the approximate tire pressure will rise to 186 kPa (27 psi) and the 1PM lamp will be ON.
To turn the TPM lamp OFF the tires must be inflated to the vehicle recommended cold placard pressure.
In order to properly maintain vehicle tire pressure, please refer to the owner's manual for additional information regarding tire inflation.
NOTE :Tire pressure should always be set based on cold inflation tire pressure (defined as the tire pressure after a vehicle has not been driven for more than 3 hours - and in outside ambient temperature).
Seasonal temperature changes will affect tire pressure, and the TPM system will monitor the actual tire pressure in the tire.
If a diagnosis of the system is required (for example, the lamp did not extinguish, or the lamp is flashing), please refer to service information available in TechCONNECT for additional information for TPM diagnosis. Please be aware that if the Wireless Control Module (WCM) is replaced, the TPM placard values may need to be reprogrammed. The TPM placard values do NOT need to be updated if the WCM has NOT been replaced, the TPM placard values are properly set at the factory.
Jan 23, 2014 |
Cars & Trucks