Code P0118

Tiny
MSKIMBA42
  • MEMBER
  • 2002 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 95,000 MILES
Changed sensor, still throwing code. Truck cranking not starting. When it does start, it is now rough running until faster speeds. Bad gad mileage. Antifreeze was green now rusty. Only had about four months now. What do I do?
Saturday, May 19th, 2018 AT 9:47 AM

1 Reply

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon.

The 118 code will not cause it not to start. I attached a description of the code and what needs to be checked for this code.

As far as not starting, you need to verify spark and fuel pressure.

Roy

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

https://www.2carpros.com/articles/car-cranks-but-wont-start

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

CIRCUIT DESCRIPTION
The engine coolant temperature (ECT) sensor is a variable resistor, sometimes called a thermistor, that measures the temperature of the engine coolant. The ECT sensor has a signal circuit and a low reference circuit. The powertrain control module (PCM) supplies 5 volts to the ECT signal circuit. When the ECT is cold, the sensor resistance is high. When the ECT increases, the sensor resistance lowers. With high sensor resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively high ECT signal voltage, which is a low temperature indication, DTC P0118 sets.

CONDITIONS FOR RUNNING THE DTC
The engine has been running for more than 60 seconds.

CONDITIONS FOR SETTING THE DTC
The ECT sensor temperature is less than -38°C (-36°F) for 20 seconds.

ACTION TAKEN WHEN THE DTC SETS
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS
If a short to a separate 5-volt source occurs this DTC may set, if this is found to be the problem a continuity test to all other PCM circuits will be necessary to diagnose the specific circuit.
After starting the engine, the ECT should rise steadily to about 90°C (194°F) then stabilize when the thermostat opens.
Use the Temperature vs Resistance Table to test the ECT sensor at Various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in poor driveability concerns. Refer to Temperature vs Resistance.
If a malfunction is not present at this time, refer to DTC P1115. See: A L L Diagnostic Trouble Codes ( DTC ) > P Code Charts > P1115
If an intermittent condition is suspected, refer to Intermittent Conditions. See: Computers and Control Systems > Initial Inspection and Diagnostic Overview > Intermittent Conditions
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Saturday, May 19th, 2018 AT 10:59 AM

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