Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Insufficient coolant temperature
for closed loop fuel control / Inspection procedure
Toyota Corolla (E120): Inspection procedure
Hint
:
- if dtcs p0115, p0116, p0117, p0118 and p0125 are output simultaneously, the engine coolant temperature sensor circuit may be open or short. Perform the troubleshooting of dtc p0115, p0117 or p0118 first.
- Read freeze frame data using the hand-held tester or the obd ii scan tool. 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.
1 Check other dtc output(in addition to dtc p0125)
- Connect the hand–held tester or the obd ii scan tool to the dlc3.
- turn the ignition switch on and push the hand–held tester or the obd ii scan tool main switch on.
- select the item ”diagnosis / enhanced obd ii / dtc info / current codes”.
- read the dtcs.
Result:

Hint
: if any other codes besides p0125 are output, perform the troubleshooting for those dtcs first.


2 Inspect thermostat


Replace engine coolant temperature sensor
Other materials:
Circuit description
Refer to dtc p0130
Hint:
the ecm provides a pulse width modulated control circuit to adjust current
through the heater. The heated
oxygen sensor heater circuit uses a relay on the b+ side of the circuit.
Monitor description
The ecm uses the heated oxygen sensor information to regulate t ...
Circuit description
Hint:
these dtcs indicate a malfunction related to the primary circuit.
If dtc p0351 is displayed, check the no.1 Ignition coil with igniter
circuit.
If dtc p0352 is displayed, check the no.2 Ignition coil with igniter
circuit.
If dtc p0353 is displayed, check the no.3 Ignition coil ...
Diagnostic trouble code chart
Notice:
when removing the part, turn the ignition switch to off.
Hint:
using sst 09843–18040, it connect the terminal tc and cg of dlc3.
If any abnormality is not found when inspecting parts, inspect the ecu and
ground points for poor contact.
If a malfunction code is displayed during ...


