DTC Troubleshooting: C1821-78, C1822-78, C1823-78, C1824-78

DTC C1821-78  : Right-Front Tire Low Air Pressure DTC C1822-78  : Left-Front Tire Low Air Pressure DTC C1823-78  : Right-Rear Tire Low Air Pressure DTC C1824-78  : Left-Front Tire Low Air Pressure

NOTE: 

• If low tire pressure is detected, the TPMS control unit sets one or more of these DTCs, and turns on the low tire pressure/TPMS indicator and the appropriate tire indicator(s). If the low tire pressure/TPMS and tire indicators come on because of a low tire pressure, and the customer corrects it before bringing the vehicle in, the DTCs will be stored, but all the indicators turn off.
• Before you troubleshoot, review the general troubleshooting information .

DTC (TPMS)

1. Problem verification

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Make sure the tires are inflated to the specified tire pressure listed on the doorjamb label.

   -3. Test-drive the vehicle.

   Does the low tire pressure/TPMS indicator go off?

   YES 

   Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting .

   NO 

   The failure is duplicated. Go to step 2.

2. Tire pressure sensor check

   -1. Check the parameter(s) below with the HDS.

   Signal	Current conditions
   	Values	Unit
   Right Front Tire Air Pressure
   Left Front Tire Air Pressure
   Right Rear Tire Air Pressure
   Left Rear Tire Air Pressure

   Is the indicated tire pressure within 40 kPa (0.4 kgf/cm 2, 6 psi) of the actual tire pressure?

   YES 

   Check for loose terminals and poor connections in the body control module connectors. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting. If they are OK, replace the body control module .

   NO 

   Check that the tire pressure sensor is properly mounted. If the mounting is OK, then replace the appropriate tire pressure sensor .