Mazda P0118 Engine Coolant Temperature Sensor Circuit High

Description

OBD-II Trouble Code Description for P0118 Mazda

Engine Coolant Temperature Circuit High

What does this mean?

OBD2 Code P0118 Mazda definition:
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

Possible sumptoms of OBD code P0118 Mazda
Symptoms of a P0118 Mazda 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

Possible causes of OBD code P0118 Mazda
A code P0118 Mazda 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 Mazda 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.

Related Codes

P0115 Mazda P0116 Mazda P0117 Mazda P0118 Mazda P0119 Mazda P0125 Mazda P0128 Mazda


The OBD2 Code Information Be Applicable For Mazda:

2013 Mazda MX-5,2013 Mazda MX-5,2013 Mazda CX-9,2013 Mazda CX-5,2013 Mazda 6,2013 Mazda 5,2013 Mazda 3,2012 Mazda MX-5,2012 Mazda BT-50,2012 Mazda 3,2011 Mazda 6,2011 Mazda 5,2011 Mazda 2,2010 Mazda 3,2009 Mazda 6,2009 Mazda 2 ,2008 Mazda 6,2008 Mazda 6,2008 Mazda 5,2008 Mazda 2,2007 Mazda CX-9,2007 Mazda CX-7,2006 Mazda MX5,2006 Mazda 6,2006 Mazda 3,2005 Mazda Atenza,2004 Mazda 6,2004 Mazda 5,2003 Mazda 2,2002 Mazda 6

 

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