P1421

System/Component
Secondary Air System
Secondary Air System Solenoid Valve
Secondary Air System Relay

Fault Code
P1421 Cylinder 4-6

Fault Type
Plausibility Yes
Signal No
Minimum Threshold No
Maximum Threshold No

Monitoring Method
check/count signal of O2-sensor
For Secondary Air System Solenoid Valve and Secondary Air System Relay, Secondary Air System Monitoring

Signal Type
Secondary Air System
ECM internal signal/value computation or comparison
Secondary Air System Solenoid Valve
on/off switching signal
Secondary Air System Relay
on/off switching signal

Operating Range
coolant temp. -10°C to 40°C

Time Length and Frequency for Monitoring/Diagnosis
13.9 sec/once per cold started trip

Criteria for storing fault code
fault during 2 cold started trips

Criteria for illuminating the MIL
fault during 2 cold started trips and end of second trip

Criteria used for determining out of range values and input component rationality check
UBATT No
Ground No
Disconnect No

Electronic Control Module (ECM)
Check of sensor signal occurs every 20 ms. The counter for checks have to be ≥ 400 during monitoring time length. Fault if the sum of the sampled O2-sensor signals for lean air/fuel ratio is less than 8.0 seconds.