Toyota 2GR-FE Manual page 280

ES–124
ES
HINT:
• Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located
far from the engine assembly.
• When any of these DTCs are set, the ECM enters fail-safe mode. The ECM turns off the Heated
Oxygen (HO2) Sensor heater in fail-safe mode. Fail-safe mode continues until the engine switch is
turned off.
• The ECM provides a pulse width modulated control circuit to adjust the current through the heater. The
HO2 sensor heater circuit uses a relay on the B+ side of the circuit.
Reference (System Diagram of Bank 1 Sensor 2):
EFI MAIN
From
Battery
Ground
DTC No.
P0037
P0057
P0038
P0058
2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
Atmospheric Air
Cover
Exhaust Gas
EFI Relay
DTC Detection Condition
Heated Oxygen (HO2) sensor heater current is less
than 0.3 A (1 trip detection logic)
Heated Oxygen (HO2) sensor heater current is more
than 2 A (1 trip detection logic)
Housing
Output Voltage
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating (Ceramic)
HO2 Sensor
Heater
EFI No. 3
+B
Sensor
E2
• Open in HO2 sensor heater circuit
• HO2 sensor heater
• Engine room junction block (EFI relay)
• ECM
• Short in HO2 sensor heater circuit
• HO2 sensor heater
• Engine room junction block (EFI relay)
• ECM
Ideal Air-Fuel Mixture
Richer - Air-Fuel Ratio - Leaner
ECM
HT1B HT1B
OX1B OX1B
EX1B
MREL
Trouble Area
A088111E14
Duty
Control
A103832E40