P0118 error code

DTC Code P0118 DTC Code: P0118 Description: Engine Coolant Temperature Sensor Circuit High Voltage Probable Causes:

1. Sensor or solenoid faulty
2. Connector terminal contact is damaged or corroded
3. Wire harness - Check harness for correct voltage, open, short to ground or short to voltage
4. Update control unit software - Check for the latest control unit update
5. Powertrain or Engine Control Module faulty

Pauline, a code P0118 may mean that one or more of the following has occurred: 1) A bad connection at the sensor 2) An open in the ground circuit between the temp. sensor and the powertrain control module (PCM) 3) An open or short in the voltage feed between the sensor and the PCM 4) A bad PCM (unlikely) 5) A bad temperature sensor. I would first check that you have a good connection at the sensor. If you have a digital voltmeter, you can also check to see if you are getting the proper signal to the sensor (with the ignition ON). One connector terminal should read 5 volts, and the other should be grounded. If you have neither one or the other, then you need to check the wiring back to the PCM. Check for broken or shorted wires. Also check for the 5 volts and ground at the coolant sensor PCM connection. If the correct reading are not present at the PCM, then the PCM needs to be repaired or replaced. An expensive proposition, I'm afraid.

P0113 Intake Air Temperature Circuit High Input

Low temperature results in a high signal voltage. When the PCM sees a signal voltage higher than 5 volts, it sets this P0113 check engine light code.

P0118 - The engine coolant temperature (ECT) sensor is a thermistor screwed into a coolant passage in the cylinder head. Sensor resistance is high when coolant temperature is low and resistance drops when coolant temperature increases. The powertrain control module (PCM) provides a 5 volt reference and a ground to the sensor. The PCM monitors voltage drop to determine coolant temperature. If the ECT reads less than freezing temp. when engine has been running for more than a few minutes, the PCM determines a circuit fault and sets this code. Or if the PCM determines the sensor resistance is out of specs, this code is set.
Potential Symptoms

Symptoms of a P0118 could include:

• Very poor fuel economy
• A no start condition
• Vehicle may start, but run very poorly, blowing black smoke, running very rough and misfiring
• Illumination of MIL

Causes

A code P0118 may mean that one or more of the following has happened:

• A bad connection at the sensor
• An open in the ground circuit between the ECT sensor and the PCM
• A short in the voltage feed between the sensor and the PCM
• A bad PCM (less likely)
• A bad temperature sensor (shorted internally)

Hi Ray:
P0118 - Engine Coolant Temperature Circuit High Input
The engine coolant temperature (ECT) sensor is a thermistor screwed into a coolant passage in the cylinder head. Sensor resistance is high when coolant temperature is low and resistance drops when coolant temperature increases. The powertrain control module (PCM) provides a 5 volt reference and a ground to the sensor. The PCM monitors voltage drop to determine coolant temperature. If the ECT reads less than freezing temp. when engine has been running for more than a few minutes, the PCM determines a circuit fault and sets this code. Or if the PCM determines the sensor resistance is out of specs, this code is set.

Symptoms of a P0118 could include:
Very poor fuel economy
A no start condition
Vehicle may start, but run very poorly, blowing black smoke, running very rough and misfiring
Illumination of MIL

A code P0118 may mean that one or more of the following has happened:
A bad connection at the sensor
An open in the ground circuit between the ECT sensor and the PCM
A short in the voltage feed between the sensor and the PCM
A bad PCM (less likely)
A bad temperature sensor (shorted internally)

Possible Solutions: First, if you have access to a scan tool, check the reading of the coolant sensor. Does it read a logical number? If so, the problem is likely intermittent. Perform a "wiggle" test by wiggling the connector and harness to the sensor while watching the reading on the scan tool. Watch for any drop-outs. Drop-outs would indicate a bad connection. If the scan tool reads an illogical temperature, check the resistance of the temperature sensor. If it is out of specs, replace it. If it is in specifications, unplug the sensor and, using a fused jumper wire, jumper the two terminals of the connector together. The temperature reading should now be maxed out to above 250 degrees F. If not, there is likely a problem with the ground circuit or voltage supply.

Check for 5 volts reference voltage at the connector. Also check for ground presence at the connector. If you do not have 5V ref. and/or ground continuity, check for these back at the PCM connector. If you have these at the PCM connector, then repair open or short between the PCM and the sensor. If you do not, remove the offending wire from the PCM and then check for proper voltage at the PCM pin. If it's present now, repair short on the circuit. If it isn't present after removing the wire and checking the pin, replace PCM

NOTE: Usually, P0118 is indicative of a bad temperature sensor, but doesn't rule out these other possibilities. If you're unsure of how to diagnose a PCM, do not attempt.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

P0118 circuit voltage high . The replacing of the PCM would need to be done at the Dealer , needs to programmed . P0118 Chevrolet Engine Coolant Temperature Circuit High Input Engine Coolant Temperature Sensor Diagnostics

Maybe a broken timing belt? Engine still turning, but cam shaft stopped turning. Pistons hitting the open valves?

Mike Graham

Engine Coolant Temperature Circuit High Input
What does that mean?

The engine coolant temperature (ECT) sensor is a thermistor screwed into a coolant passage in the cylinder head. Sensor resistance is high when coolant temperature is low and resistance drops when coolant temperature increases. The powertrain control module (PCM) provides a 5 volt reference and a ground to the sensor. The PCM monitors voltage drop to determine coolant temperature. If the ECT reads less than freezing temp. when engine has been running for more than a few minutes, the PCM determines a circuit fault and sets this code. Or if the PCM determines the sensor resistance is out of specs, this code is set.
FB.init("dd7d9e9681341cde77587bc6a2029f6f"); OBD-Codes.com on Facebook Potential Symptoms

Symptoms of a P0118 could include:

• Very poor fuel economy
• A no start condition
• Vehicle may start, but run very poorly, blowing black smoke, running very rough and misfiring
• Illumination of MIL

Causes

A code P0118 may mean that one or more of the following has happened:

• A bad connection at the sensor
• An open in the ground circuit between the ECT sensor and the PCM
• A short in the voltage feed between the sensor and the PCM
• A bad PCM (less likely)
• A bad temperature sensor (shorted internally)

Possible Solutions

First, if you have access to a scan tool, check the reading of the coolant sensor. Does it read a logical number? If so, the problem is likely intermittent. Perform a "wiggle" test by wiggling the connector and harness to the sensor while watching the reading on the scan tool. Watch for any drop-outs. Drop-outs would indicate a bad connection. If the scan tool reads an illogical temperature, check the resistance of the temperature sensor. If it is out of specs, replace it. If it is in specifications, unplug the sensor and, using a fused jumper wire, jumper the two terminals of the connector together. The temperature reading should now be maxed out to above 250 degrees F. If not, there is likely a problem with the ground circuit or voltage supply.

Check for 5 volts reference voltage at the connector. Also check for ground presence at the connector. If you do not have 5V ref. and/or ground continuity, check for these back at the PCM connector. If you have these at the PCM connector, then repair open or short between the PCM and the sensor. If you do not, remove the offending wire from the PCM and then check for proper voltage at the PCM pin. If it's present now, repair short on the circuit. If it isn't present after removing the wire and checking the pin, replace PCM

NOTE: Usually, P0118 is indicative of a bad temperature sensor, but doesn't rule out these other possibilities. If you're unsure of how to diagnose a PCM, do not attempt. The sensor is located near the thermostat housing on the top of the engine

Engine coolant temperature (ECT) sensor is a thermistor screwed into a coolant passage in the cylinder head. Sensor resistance is high when coolant temperature is low and resistance drops when coolant temperature increases. The powertrain control module (PCM) provides a 5 volt reference and a ground to the sensor. The PCM monitors voltage drop to determine coolant temperature. If the ECT reads less than freezing temp. when engine has been running for more than a few minutes, the PCM determines a circuit fault and sets this code. Or if the PCM determines the sensor resistance is out of specs, this code is set.

The reference values given below are measured between ECM terminal 72 and ground...

When measuring input / output voltage be careful not to use ECM ground terminals. The ECM will enter fail safe mode once a malfunction is detected and the MI will light up.

Usually, P0118 is indicative of a bad temperature sensor, but doesn't rule out these other possibilities. If you're unsure of how to diagnose a PCM, do not attempt.

Keep us updated.

P0118 - Engine Coolant Temperature Circuit High Input

What does that mean?
The engine coolant temperature (ECT) sensor is a thermistor screwed into a coolant passage in the cylinder head. Sensor resistance is high when coolant temperature is low and resistance drops when coolant temperature increases. The powertrain control module (PCM) provides a 5 volt reference and a ground to the sensor. The PCM monitors voltage drop to determine coolant temperature. If the ECT reads less than freezing temp. when engine has been running for more than a few minutes, the PCM determines a circuit fault and sets this code. Or if the PCM determines the sensor resistance is out of specs, this code is set.

Symptoms of a P0118 could include:
* Very poor fuel economy
* A no start condition
* Vehicle may start, but run very poorly, blowing black smoke, running very rough and misfiring
* Illumination of MIL

Causes
A code P0118 may mean that one or more of the following has happened:
* A bad connection at the sensor
* An open in the ground circuit between the ECT sensor and the PCM
* A short in the voltage feed between the sensor and the PCM
* A bad PCM (less likely)
* A bad temperature sensor (shorted internally)

Possible Solutions
First, if you have access to a scan tool, check the reading of the coolant sensor. Does it read a logical number? If so, the problem is likely intermittent. Perform a "wiggle" test by wiggling the connector and harness to the sensor while watching the reading on the scan tool. Watch for any drop-outs. Drop-outs would indicate a bad connection. If the scan tool reads an illogical temperature, check the resistance of the temperature sensor. If it is out of specs, replace it. If it is in specifications, unplug the sensor and, using a fused jumper wire, jumper the two terminals of the connector together. The temperature reading should now be maxed out to above 250 degrees F. If not, there is likely a problem with the ground circuit or voltage supply.

Check for 5 volts reference voltage at the connector. Also check for ground presence at the connector. If you do not have 5V ref. and/or ground continuity, check for these back at the PCM connector. If you have these at the PCM connector, then repair open or short between the PCM and the sensor. If you do not, remove the offending wire from the PCM and then check for proper voltage at the PCM pin. If it's present now, repair short on the circuit. If it isn't present after removing the wire and checking the pin, replace PCM

NOTE: Usually, P0118 is indicative of a bad temperature sensor, but doesn't rule out these other possibilities. If you're unsure of how to diagnose a PCM, do not attempt.

Other engine coolant engine light codes: P0115, P0116, P0117, P0118, P0119, P0125, P0128

Hope helps.

If you changed the coolant temperature sensor and it had a 5 volt ref signal to it then you replaced the wrong part. You need to replace the coolant temperature sending unit.  The coolant temp "sensor" is an input to the ECM for your fuel injection system. The coolant temp "sending unit" is for coolant temp reading at the gauge, It is an NTC switch (negative temperature coefficient) which means as temp increases/resistance decreases.