A20024
ECM
A/F Sensor
EFI Main Relay
EFI Fuse
From
Battery
Ground
AF+
AFHT
Duty
Control
Heater
Sensor
Reference
AF–
IGN Fuse
–
DIAGNOSTICS
ENGINE (2RZ–FE, 3RZ–FE)
DI–61
323
Author:
Date:
2003 TOYOTA TACOMA (RM1002U)
DTC
P0135
Oxyge (A/F) Sensor Heater Circuit
(Bank 1 Sensor 1)
CIRCUIT DESCRIPTION
Refer to DTC P2195 on page DI–185.
HINT:
This DTC is related A/F sensor, although the caption is oxygen sensor.
The ECM provides a pulse width to control current through the heater. The oxygen sensor heater circuit
uses a relay on the B+ side of the circuit.
DTC No.
DTC Detecting Condition
Trouble Area
P0135
When the heater operates, heater current exceeds 8 A
(2 trip detection logic)
Open or in heater circuit of A/F sensor
A/F
h
t
Heater current is 0.3 A or less when the heater operates
(2 trip detection logic)
sensor eaer
ECM
WIRING DIAGRAM
Refer to DTC P0134 on page DI–50.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using the hand–held tester or the OBD II scan tool, as freeze frame data records
the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining
whether the vehicle was running or stopped, the engine was warmed up or not, the air–fuel ratio was lean
or rich, etc. at the time of the malfunction.
DIB26–01
B08732
HT
+B
Ohmmeter
I05027
3
1
2
5
1
2
5
3
DI–62
–
DIAGNOSTICS
ENGINE (2RZ–FE, 3RZ–FE)
324
Author:
Date:
2003 TOYOTA TACOMA (RM1002U)
1
Check resistance of A/F sensor heater.
PREPARATION:
Disconnect the sensor connector.
CHECK:
Using an ohmmeter, measure the resistance between terminals
+B and HT.
OK:
at 20°C (68°F)
0.8 – 1.4 Ω
at 800°C (1,472°F)
1.8 – 3.2 Ω
NG
Replace A/F sensor.
OK
2
Check EFI main relay (Marking: EFI).
PREPARATION:
Remove the EFI main relay from RB No. 2.
CHECK:
Inspect the EFI main relay.
OK:
Condition
Tester connection
Specified condition
C
t
t
1 – 2
Continuity
onsan
3 – 5
No continuity
Apply B+ between
terminals 1 and 2.
3 – 5
Continuity
NG
Replace EFI main relay.
OK
A18845
AFHT
–
DIAGNOSTICS
ENGINE (2RZ–FE, 3RZ–FE