C1821 BMW Fault Code
Check C1821 OBD Fault Code ReasonBrake Switch Circuit Input Malfunction Indicates PCM did not receive a brake pedal position (BPP) input. Open or short in BPP circuit Open or short in stoplamp circuits damaged PCM Malfunction in module(s) connected to BPP circuit.
(Rear Electronic Module [REM] Windstar and LS6/LS8 or Lighting Control Module (LCM) Continental and Town Car. Damaged brake switch Misadjusted brake switch Check for proper function of stoplamps.
C1821 Code Symptoms :
There are currently two main types of cylinder deactivation used today, depending on the type of engine. C1821 code for the pushrod design which uses solenoids to alter the oil pressure delivered to the lifters. In their collapsed state, the lifters are unable to elevate their companion pushrods under the valve rocker arms, resulting in valves that cannot be actuated and remain closed.
Diagnosis And Repairing C1821
C1821 OBD 2 code on vehicles with electronically controlled automatic transmissions, the 3-4 shift solenoid is responsible for actuating the hydraulic circuits to activate clutches or bands that change gears inside the automatic transmission.
How to fix C1821 code ?
- Damaged ECM
- Damaged ECM
- Incorrect fuel filler cap used
- Faulty Crankshaft Position Sensor (POS)
Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code C1821, so consult the manual to locate the brake fluid reservoir.
Bear in mind that a low fluid level can set code C1821 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.
