Toyota 2GR-FE Manual page 281

DTC No.
P0141 Cumulative heater resistance correction value exceeds
P0161 the acceptable threshold. (2 trip detection logic)
HINT:
• Bank 1 refers to the bank that includes cylinder No. 1.
• Bank 2 refers to the bank that does not include cylinder No. 1.
• Sensor 1 refers to the sensor closest to the engine assembly.
• Sensor 2 refers to the sensor farthest away from the engine assembly.
MONITOR DESCRIPTION
The sensing position of the Heated Oxygen (HO2) sensor has a zirconia element which is used to detect
the oxygen concentration in the exhaust gas. If the zirconia element is at the appropriate temperature,
and the difference between the oxygen concentrations surrounding the inside and outside surfaces of the
sensor is large, the zirconia element generates voltage signals. In order to increase the oxygen
concentration detecting capacity of the zirconia element, the ECM supplements the heat from the exhaust
with heat from a heating element inside the sensor.
Heated oxygen sensor heater range check (P0037,P0038, P0057 and P0058):
The ECM monitors the current applied to the O2 sensor heater to check the heater for malfunctions. If the
current is below the threshold value, the ECM will determine that there is an open circuit in the heater. If
the current is above the threshold value, the ECM will determine that there is a short circuit in the heater.
Example:
The ECM sets DTC P0038 or P0058 when the current in the HO2 sensor heater is more than 2 A.
Conversely, when the heater current is less than 0.3 A, DTC P0037 or P0057 is set.
Heated oxygen sensor heater performance (P0141 and P0161):
After the accumulated heater ON time exceeds 100 seconds, the ECM calculates the heater resistance
using the battery voltage and the current applied to the heater. If the resistance is above the threshold
value, the ECM will determine that there is a malfunction in the HO2S heater and set DTC P0141 and
P0161.
MONITOR STRATEGY
Related DTCs
Required sensors / components (Main)
Required sensors / components (Sub)
Frequency of operation
Duration
MIL operation
Sequence of operation
TYPICAL ENABLING CONDITIONS
All:
Monitor runs whenever following DTCs are not present
2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
DTC Detection Condition
• HO2 sensor heater
• ECM
P0037: Heated oxygen sensor heater (bank 1 sensor 2) open/short
(Low electrical current)
P0038: Heated oxygen sensor heater (bank 1 sensor 2) open/short
(High electrical current)
P0057: Heated oxygen sensor heater (bank 2 sensor 2) open/short
(Low electrical current)
P0058: Heated oxygen sensor heater (bank 2 sensor 2) open/short
(High electrical current)
P0141: Heated oxygen sensor heater performance (bank 1 sensor 2)
P0161: Heated oxygen sensor heater performance (bank 2 sensor 2)
Heated oxygen sensor heater (bank 1 sensor 2)
Heated oxygen sensor heater (bank 2 sensor 2)
Vehicle speed sensor
Continuous
1 second: P0037, P0038, P0057 and P0058
10 seconds: P0141 and P0161
Immediate: P0037, P0038, P0057 and P0058
2 driving cycles: P0141 and P0161
None
None
ES–125
Trouble Area
ES