Runs intermittent and idles rough

Tiny
BILL QUIRK
  • MEMBER
  • 2002 MERCURY MOUNTAINEER
  • 4.0L
  • V6
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
My vehicle all of a sudden the coolant temperature gauge stopped working and the outside temperature just showed - - and the overdrive light flashes really fast. Please help me.
Friday, May 8th, 2020 AT 11:38 AM

3 Replies

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

The first thing I would do is have it checked for codes. You can go to a parts store and they will read them for free.

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

Once I know the codes, I can help narrow the area of failure for you.

The overdrive light is transmission related. There is a fault code stored for that.

https://www.2carpros.com/articles/automatic-transmission-problems

The coolant gauge could be the coolant sensor which sends a signal to the ECM for the gauge.

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

https://www.2carpros.com/articles/symptoms-of-a-bad-coolant-temperature-sensor

Roy

REMOVAL
1. Disconnect the battery ground cable.
2. Drain the cooling system.

imageOpen In New TabZoom/Print

3. Disconnect the ECT sensor electrical connector.

imageOpen In New TabZoom/Print

4. Remove the ECT sensor retaining clip and remove the ECT sensor.

INSTALLATION
1. To install, reverse the removal procedure.
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Friday, May 8th, 2020 AT 11:49 AM
Tiny
BILL QUIRK
  • MEMBER
  • 4 POSTS
Koeo codes po113/ po118/ po123/
Po453/po708/ po713/
P1000/p1401/p1565/p1702
Koer codes. Po113/po118/po123/po708
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Saturday, May 9th, 2020 AT 1:25 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
The 113 is intake air temperature sensor. It is located on the intake hose from the mass air flow to the throttle body.

https://www.2carpros.com/articles/replace-an-air-intake-boot

118 is for the coolant temp sensor. It is located by the thermostat housing. It is a 2 wire sensor.

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

123 is for the throttle position sensor?

The 708 is for the transmission range sensor on the side of the transmission.

https://www.2carpros.com/articles/automatic-transmission-problems

https://www.2carpros.com/articles/how-a-neutral-safety-switch-works

Roy

The Intake Air Temperature (IAT) sensors (Figure 33) and integrated Mass Air Flow (MAF) type (Figure 36), are thermistor devices in which resistance changes with temperature The electrical resistance of a thermistor decreases as the temperature increases, and increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signals to the PCM corresponding to temperature.

Thermistor-type sensors are considered passive sensors. A passive sensor is connected to a voltage divider network so that varying the resistance of the passive sensor causes a variation in total current flow.

Voltage that is dropped across a fixed resistor in a series with the sensor resistor determines the voltage signal at the PCM. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor.

The IAT provides air temperature information to the PCM. The PCM uses the air temperature information as a correction factor in the calculation of fuel, spark and MAF.

The IAT sensor provides a quicker temperature change response time than the ECT or CHT sensor.

Supercharged vehicles use (2) IAT sensors. Both sensors are thermistor type devices and operate as above. However, one is located before the supercharger at the air cleaner for standard OBD II/cold weather input, while a second sensor (IAT2) is located after the supercharger in the intake manifold. The IAT2 sensor located after the supercharger provides air temperature information to the PCM to control border-line spark and to help determine intercooler efficiency.

Currently two types of IAT2 sensors are used. A screw in type (Figure 33) and an integrated type, witch is part of the Thermal Manifold Absolute Pressure (TMAP) sensor (Figure 40). The TMAP sensor consists of a IAT thermistor and a Manifold Absolute Pressure (MAP) sensor. The thermistor portion of the TMAP is used for IAT2 function and operates in the same manner as a non-integrated IAT2. For additional information on the MAP portion of the TMAP, refer to the Thermal Manifold Absolute Pressure Sensor description and operation.
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Sunday, May 10th, 2020 AT 2:46 AM

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