HO2S Heater Monitor

OBD System Description - HO2S Heater Monitor

HO2S Heater Control Circuit Bank 1 Sensor 1 / HO2S Heater Control Circuit Bank 2 Sensor 1
DTC

Electrical check:
P0030 Refer to DTC P0030: HO2S Heater Control Circuit Bank 1 Sensor 1. P0030
P0031 Refer to DTC P0031: HO2S Heater Control Circuit Low Voltage Bank 1 Sensor 1. P0031
P0032 (Bank 1) Refer to DTC P0032: HO2S Heater Control Circuit High Voltage Bank 1 Sensor 1. P0032
P0050 Refer to DTC P0050: HO2S Heater Control Circuit Bank 2 Sensor 1. P0050
P0051 Refer to DTC P0051: HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1. P0051
P0052 (Bank 2) Refer to DTC P0052: HO2S Heater Control Circuit High Voltage Bank 2 Sensor 1. P0052

Heater resistance check:
P0030 (Bank 1) Refer to DTC P0030: HO2S Heater Control Circuit Bank 1 Sensor 1. P0030
P0050 (Bank 2) Refer to DTC P0050: HO2S Heater Control Circuit Bank 2 Sensor 1. P0050

MONITOR STRATEGY DESCRIPTION
Electrical check:
This Diagnosis is to detect an Electrical malfunction, short circuit to VB, SCG, OL. The heater driver is capable of detecting OL and SCB when in the "ON" State and will detect the SCG only when in the "OFF" state. The heater power is controlled by a PWM signal, the driver will be placed alternately in an "ON" and then "OFF" state.

Heater resistance check:
The upstream oxygen sensor heater circuit shall detect any loss in heater power that would cause a drop in the sensor operating temperature, thereby possibly causing exhaust gas emissions to rise above the applicable standards or prevent the sensor signal from being used as a diagnostic system monitoring device.

MALFUNCTION CRITERIA AND THRESHOLD VALUE(S)
Electrical check:
Direct check by Hardware

Heater resistance check:
Internal resistance of upstream oxygen sensor >= 1,200 Ohms
Number of completed diagnosis cycles >= 60
Number of diagnosis cycles in which temperature deviation exceeding limits present >= 40

SECONDARY PARAMETERS AND ENABLE CONDITIONS
Electrical check:
Enable Conditions:
IGN = "ON", Eng = "ON"
Batt volts > 10.968 V
Diagnostic = Enabled
SCB Diagnosis:
PWM signal > 1.5154 V (based on VB = 14 V) (1.1718%)
Or
Exhaust Temp. > 99.975 degrees C
SCG Diagnosis:
PWM signal > 13.94 V (based on VB = 14 V) (99.2187%)
OL
Diagnosis:
PWM signal > 1.5154 V (based on VB = 14 V) (1.1718%)
Or
PWM signal< 13.94 V (based on VB = 14 V) (99.2187%)
Timer > 2500 ms

Heater resistance check:
10.9687 V < Battery voltage < 16.046 V
0.87 V (based on VB = 14 V) (0.39%)
<= Heater driver PWM duty cycle
<= 13.9419 V (based on VB = 14 V) (99.60%)
Timer > 240 s
Exhaust gas temperatures at the lambda sensor upstream catalyst <= 599.975 degrees C
Cooling energy of exhaust gas at sensor location > 0.0079 kWh (27685 J)
This diagnostic is inhibited if any of the following DTC's are present.
No MAF error
No MAF/TPS error
No upstream O2 sensor error

NOTE: If forced Closed Loop occurs, one or more of the following DTC's will be stored. If the Open Circuit (OC) diagnostics pass, then an HO2S Heater Malfunction will be stored as the root cause for forced Closed Loop.
B1S1-P0030 (HO2S Heater Malfunction)
B2S1-P0050 (HO2S Heater Malfunction)

TIME LENGTH AND FREQUENCY
Electrical check:
Recurrence rate: 100 ms
Heater resistance check:
Recurrence rate:
Diagnosis: Once per driving cycle until diagnosis results obtained
Internal Diagnosis Loop: 1 s until number of diagnostic cycles exceeded

HO2S Heater Control Circuit Bank 1 Sensor 2 / HO2S Heater Control Circuit Bank 2 Sensor 2
DTC
Electrical check:
P0036 Refer to DTC P0036: HO2S Heater Control Circuit Bank 1 Sensor 2.P0036
P0037 Refer to DTC P0037: HO2S Heater Control Circuit Bank 1 Sensor 2. P0037
P0038 (Bank 1) Refer to DTC P0038: HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2. P0038
P0056 Refer to DTC P0056: HO2S Heater Control Circuit Bank 2 Sensor 2. P0056
P0057 Refer to DTC P0057: HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 2. P0057
P0058 (Bank 2) Refer to DTC P0058: HO2S Heater Control Circuit High Voltage Bank 2 Sensor 2. P0058
Heater resistance check:
P0036 (Bank 1) Refer to DTC P0036: HO2S Heater Control Circuit Bank 1 Sensor 2. P0036
P0056 (Bank 2) Refer to DTC P0056: HO2S Heater Control Circuit Bank 2 Sensor 2. P0056

MONITOR STRATEGY DESCRIPTION
Electrical check:
This Diagnosis is to detect an Electrical malfunction, short circuit to VB, SCG, OL. The heater driver is capable of detecting OL and SCB when in the "ON" state and will detect the SCG only when in the "OFF" state. The heater power is controlled by a PWM signal, the driver will be placed alternately in an "ON" and then "OFF" state.

Heater resistance check:
The downstream oxygen sensor heater circuit shall detect any loss in heater power that would cause a drop in the sensor operating temperature, thereby possibly causing exhaust gas emissions to rise above the applicable standards or prevent the sensor signal from being used as a diagnostic system monitoring device.

MALFUNCTION CRITERIA AND THRESHOLD VALUE(S)
Electrical check:
Direct check by Hardware Fail Time > 2,500 ms

Heater resistance check:
Internal resistance of downstream oxygen sensor ≥ 7,000 Ohms
Number of completed diagnosis cycles ≥ 60
Number of diagnosis cycles in which temperature deviation exceeding limits present ≥ 40

SECONDARY PARAMETERS AND ENABLE CONDITIONS
Electrical check:
Enable Conditions:
IGN = "ON", Eng = "ON"
Batt volts > 10.968 V
Diagnostic = Enabled
SCB Diagnosis:
PWM signal > 1.5154 V (based on VB = 14 V) (1.1718%)
Or
Exhaust Temp. > 39.975 degrees C
SCG Diagnosis:
PWM signal > 13.94 V (based on VB = 14 V) (99.2187%)
OL Diagnosis:
PWM signal > 1.5154 V (based on VB = 14 V) (1.1718%)
Or
PWM signal < 13.88 V (based on VB = 14 V) (99.218%)
Heater resistance check:
10.9687 V < Battery voltage < 16.0468 V
0.87 V (based on VB = 14 V) (0.39%)
≤Heater driver PWM duty cycle
≤13.9419 V (based on VB = 14 V) (99.60%)
Timer > 120 s
Exhaust gas temperatures at the lambda sensor downstream catalyst
≤599.975 degrees C
Cooling energy of exhaust gas at sensor location >
27685 J
This diagnostic is inhibited if any of the following DTC's are present.
MAF error
MAF/TPS error

NOTE: If forced Closed Loop occurs, one or more of the following DTC's will be stored. If the Open Circuit (OC) diagnostics pass, then an HO2S Heater Malfunction will be stored as the root cause for forced Closed Loop.
B1S2-P0036 (HO2S Heater Malfunction)
B2S2-P0056 (HO2S Heater Malfunction)

TIME LENGTH AND FREQUENCY
Electrical check:
Recurrence rate: 100 ms

Heater resistance check:
Diagnosis: Once per driving cycle until diagnosis results obtained
Recurrence rate:
Internal Diagnosis Loop: 1 s until number of diagnostic cycles exceeded

Mode $06 Data:

MODE $06 Data