ATTENTION: Diagnosis by the substitution method from the donor car is PROHIBITED. Substitution of control modules does not guarantee confirmation of the fault and, in addition, may cause additional faults in the vehicle being tested and/or in the vehicle from which the modules are removed.
1. Check the customer's complaint. Ask the driver as much as possible to make it easier to diagnose the cause. Check which of the two types of warnings (A or B) displayed in the tire pressure monitoring system when the ignition is switched on (translation from position «OFF» into position «ON»).
- (A) Check tire pressure warnings. Activating the low tire pressure warning turns on the low tire pressure warning light, which is constantly lit. This warning may be accompanied by a text message such as CHECK TIRE PRESSURE (Check tire pressure) (see the operating documentation for the car owner). It is NOT MANDATORY to use the diagnostic system recommended by the manufacturer. Diagnostic Trouble Codes (DTC) are not generated with this type of alert. To turn off the warning, you must set the correct tire pressure with the ignition on (including spare wheel) in accordance with the instructions in the vehicle's operating manual or according to the data on the plates in the driver's/passenger's door openings. It is not necessary to drive the car to reset the tire pressure check warning - the low pressure sensors provide new information when the tire pressure changes.
- (B) System malfunction warnings. When a system malfunction is detected, the low tire pressure warning light flashes for approximately 75 seconds and then stays on. Inspect for obvious signs of damage and system integrity. Check for low pressure sensors in all four wheels (note: the low tire pressure sensor is equipped with a metal valve stem, not a rubber one).
NOTE: Tire pressure must be set under the following conditions:
- using a calibrated pressure gauge;
- on cold tires (the vehicle is stationary for at least one hour in an open area, not in a temperature controlled garage).
NOTE: If the tire pressure monitoring system warning does not go away within two minutes, the cause may be an incorrect calibration of the pressure gauge or warm tires. Perform the following steps until the warning is cleared:
- increase tire pressure by 3 psi. inch;
- wait two minutes;
- if the tire temperature is equal to the ambient temperature and a calibrated pressure gauge is available, bring the tire pressure up to the correct pressure.
NOTE: Tire pressure adjustment is part of the owner's periodic maintenance routine. Tire pressure adjustments caused by the owner's failure to maintain the vehicle are not eligible for warranty claims.
2. Check for diagnostic trouble codes (DTC) and refer to the DTC Index.
NOTE: If there is no communication between the tester and the tire pressure monitoring system module, the following steps are recommended:
- remove the fuse for the power supply circuit of the tire pressure monitoring system, inspect and reinsert (if it's correct); check if the connection is restored;
- remove the ignition circuit fuse of the tire pressure monitoring system (if applicable), inspect and replace (if it's correct); check if the connection is restored;
- with the ignition on, refer to the electrical diagram and check for an open in the power, ignition and ground circuits of the tire pressure monitoring system module;
- perform a CAN network integrity check using the manufacturer approved diagnostic system.
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