HO2S Heater Monitor
OBD System Description - HO2S Heater MonitorHO2 B1S1 Heater Short Low
DTC Description / Detecting Condition / Confirmation Procedure
P0031 refer to DTC P0031: HO2S Heater Control Circuit Low Voltage Sensor 1. P0031
Monitor Strategy Description
Detects a short to ground or open circuit of O2 sensor heater circuit output. The output driver hardware sets "Failure Criteria Met = TRUE" if output state does not equal the expected return voltage.
Malfunction Criteria
Fail Criteria Met = TRUE
Enable Conditions
Disabling Faults Present = FALSE
AND Ignition Voltage ≥ 11 V
AND Ignition Voltage ≤ 16 V
AND Enable Time delay ≥ 0.5 s
Time required
Time Length and Frequency:
40 test failures within a 80 test samples.
Failure Time:
Continuous monitoring every 125 ms.
HO2 B1S1 Heater Short High
DTC Description / Detecting Condition / Confirmation Procedure
P0032 refer to DTC P0032: HO2S Heater Control Circuit High Voltage Sensor 1. P0032
Monitor Strategy Description
Detects a short to battery O2 sensor heater circuit output. The output driver hardware sets "Failure Criteria Met = TRUE" if output state does not equal the expected return voltage.
Malfunction Criteria
Fail Criteria Met = TRUE
Enable Conditions
Disabling Faults Present = FALSE
AND Ignition Voltage ≥ 11 V
AND Ignition Voltage ≤ 16 V
AND Enable Time delay ≥ 0.5 s
Time required
Time Length and Frequency:
40 test failures within a 80 test samples.
Failure Time:
Continuous monitoring every 125 ms.
HO2 B1S2 Heater Short Low
DTC Description / Detecting Condition / Confirmation Procedure
P0037 refer to DTC P0037: HO2S Heater Control Circuit Low Voltage Sensor 2. P0037
Monitor Strategy Description
Detects a short to ground or open circuit of O2 sensor heater circuit output. The output driver hardware sets "Failure Criteria Met = TRUE" if output state does not equal the expected return voltage.
Malfunction Criteria
Fail Criteria Met = TRUE
Enable Conditions
Disabling Faults Present = FALSE
AND Ignition Voltage ≥ 11 V
AND Ignition Voltage ≤ 16 V
AND Enable Time delay ≥ 0.5 s
Time required
Time Length and Frequency:
40 test failures within a 80 test samples.
Failure Time:
Continuous monitoring every 125 ms.
HO2 B1S2 Heater Short High
DTC Description / Detecting Condition / Confirmation Procedure
P0038 refer to DTC P0038: HO2S Heater Control Circuit High Voltage Sensor 2. P0038
Monitor Strategy Description
Detects a short to battery O2 sensor heater circuit output. The output driver hardware sets "Failure Criteria Met = TRUE" if output state does not equal the expected return voltage.
Malfunction Criteria
Fail Criteria Met = TRUE
Enable Conditions
Disabling Faults Present = FALSE
AND Ignition Voltage ≥ 11 V
AND Ignition Voltage ≤ 16 V
AND Enable Time delay ≥ 0.5 s
Time required
Time Length and Frequency:
40 test failures within a 80 test samples.
Failure Time:
Continuous monitoring every 125 ms.
HO2 B1S1 Heater (Heater Current)
DTC Description / Detecting Condition / Confirmation Procedure
P0135 refer to DTC P0135: HO2S Heater Performance Sensor 1. P0135
Monitor Strategy Description
Compares the current that is passing through the O2 Heater to a low limit.
Malfunction Criteria
Filtered O2 Heater Current < See table.
Enable Conditions
Ignition ON? =
AND Engine Run Time > 60 s
AND Heater Duty Cycle Commanded > 0.1%
AND Max. - Min. Commanded Duty Cycle < 0.05%
AND Enable Timer ≥ 0.375 s
Time required
Time Length and Frequency:
20 test failures within a 40 test samples.
Failure Time:
Continuous monitoring every 125 ms.
HO2 B1S2 Heater (Heater Current)
DTC Description / Detecting Condition / Confirmation Procedure
P0141 refer to DTC P0141: HO2S Heater Performance Sensor 2. P0141
Monitor Strategy Description
Compares the current that is passing through the O2 Heater to a low limit.
Malfunction Criteria
Filtered O2 Heater Current < See table.
Enable Conditions
Ignition ON? =
AND Engine Run Time > 30 s
AND Heater Duty Cycle Commanded > 0.1%
AND Max - Min. Commanded Duty Cycle < 0.05%
AND Enable Timer ≥ 0.375 s
Time required
Time Length and Frequency:
60 test failures within a 70 test samples.
Failure Time:
Continuous monitoring every 125 ms.