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DIAGNOSTICS
ENGINE (5VZ–FE)
DI–263
525
Author:
Date:
2003 TOYOTA TACOMA (RM1002U)
DTC
P0116
Engine Coolant Temperature Circuit Range/
Performance Problem
DTC
P0125
Insufficient Coolant Temperature for Closed
Loop Fuel Control
CIRCUIT DESCRIPTION
Refer to DTC P0115 on page DI−258.
DTC No.
DTC Detection Condition
Trouble Area
P0116
When THW 35°C (95°F) and 60°C (140°F), THA
–6.7°C (19.4°F) when starting engine, conditions (a) and (b)
continue: (2 trip detection logic)
(a) Vehicle speed is changing (Not stable)
(b) Water temp. change is lower than 3°C (37.4°F) from water
temp. since when starting engine
In case that reading value of water temp. sensor will not
change more than 1°C (33.8°F) even after repeating 6 trips
(detection logic) of adjusting speed pattern with THW more
than 60°C (140°F) when starting engine
Cooling system
If THW < –6.7°C (20°F) or THA < –6.7°C (20°F) 20 min. or
more after starting engine, engine coolant temp. sensor value
is 20°C (68°F) or less (2 trip detection logic)
Engine coolant temp. sensor
P0125
If THW –6.7°C (20°F) and THA –6.7°C (20°F) and 10°C
(50°F) at engine start, 5 min. or more after starting engine,
engine coolant temp. sensor value is 20°C (48°F) or less
(2 trip detection logic)
If THW 10°C (50°F) and THA 10°C (50°F) at engine
start, 2 min. or more after starting engine, engine coolant temp.
sensor value is 20°C (48°F) or less (2 trip detection logic)
INSPECTION PROCEDURE
HINT:
If DTCs P0115, P0116, P0117, P0118 and P0125 are output simultaneously, engine coolant tempera-
ture sensor circuit may be open. Perform the troubleshooting of DTC P0115 first.
Read freeze frame data using the hand–held tester or the OBD II scan tool, as freeze frame data re-
cords the engine conditions when a malfunction is detected. When troubleshooting, it is useful for de-
termining 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.
1
Are there any other codes (besides DTC