Question about 1998 Honda Accord
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
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)
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
Posted on Jun 06, 2010
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Posted on Jan 02, 2017
Try these things. Why don't you call the Honda customer service at 1-800-999-1009 have your radio serial number and VIN to your car and they will help you to unlock your radio. If you don't have the serial code to your radio and you are the original owner they will tell you have to get the code and turn it back on and also how to get your serial number to you radio to unlock it. Here are some websites too: www.Radio-code.com & www.webcrawler.com type in radio unlock code. But if you are the original owner you should have a white card that came with the car. It says HONDA Anti-theft radio Identification card . It has you code number and serial number on it and how to put in the code to unlock the radio.
Posted on Aug 02, 2009
5 MAP Sensor (Manifold Absolute Pressure) mechanical problem / disconnected piping. I'm not completely sure of this one but most auto parts stores will give you the code meaning for free. Autozone is one who does this all the time. Sorry this is all I can tell you.
Posted on Dec 29, 2009
No-one is ever particularly happy to here this, but this is the way it is; we do have to keep in mind that the original idea of codes on radios was to prevent people who steal them from being able to use them.
So, if an audio unit with theft protection is disconnected from electrical power, you must enter a unique code number into the unit or it will not work. This code and the audio unit’s serial number are listed on the anti-theft ID card that comes with the vehicle. If this card is lost, you must obtain the audio unit serial number in order to get the radio code (some people say that they have found the code on a sticker inside the glove compartment, but I wouldn’t count on that). Some newer vehicles allow you to retrieve the audio unit serial number electronically from the radio. Refer to your owner’s manual for the specific procedure (the following usually will work: Turn the radio off. Push the preset 1, preset 6, and power buttons at the same time, then quickly release. The serial number will come up in two sets of numbers.)
Some older vehicles (model year 2003 and older) require a visit to the dealer in order to retrieve the audio unit serial number (or you can remove the unit and get the serial number from the back of the radio). Once you have the audio unit serial number, you can call Auto Customer Service at (800) 999-1009 or have the dealer look up the radio code.
Here is the URL for the Honda Owner page. If you register (no charge) you are able to get radio codes using the VIN number of your car, the serial number of your radio, and the Phone Number and Zip Code that you give them when you register.
Hope this helps you with the process.
Posted on Jan 04, 2010
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if the above suggestion is not successful ,then unfortunately the code will not be available for free (or cheap ) from anywhere on the Internet.
Main Dealer or a Decoding Service only
Posted on May 29, 2010
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