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Electronic Engine Contol Sensors 


Component description and operation, removal and installation.

This section deals with the control sensors affiliated with the Electronic Engine Control (EEC) and the Powertrain Control Module (PCM).  Various switch and sensor failures were commonly responsible for some drivability problems with the 1989 - 1995 Taurus SHO's, however these problems have yet to repeat themselves with the Third Generation car's.  The following is a list of sensors, their operational description, and the removal and installation procedure, where applicable.

Powertrain Control Module (PCM) | Throttle Position (TP) Sensor | Mass Air Flow (MAF) Sensor | Intake Air Temperature (IAT) Sensor | Idle Air Control (IAC) Valve | Engine Coolant Temperature (ECT) Sensor Heated Oxygen Sensor (HO2S) | Camshaft Position (CMP) Sensor | Knock Sensor (KS) | Power Steering Pressure (PSP) Switch | Vehicle Speed Sensor (VSS)
 

POWERTRAIN CONTROL MODULE (PCM)

The powertrain control module (PCM) performs the following functions:

Removal

1. Disconnect battery ground cable.
2. Remove cowl deflector.
3. Remove screw securing the ground cable of the engine control sensor wiring to the dash panel.
4. Loosen engine control sensor wiring to PCM connector retainer bolt.
5. Remove engine control sensor wiring from PCM.
6. Remove retaining nuts and powertrain control module insulator from dash panel.
7. Remove powertrain control module.

Installation

1. Follow removal procedure in reverse order.
2. Tighten insulator retaining nuts to 8-12 N-m (71-106 lb-in).
3. Tighten engine control sensor wiring retainer bolt to 3.7 N-m (32 lb-in).
4. Tighten engine control sensor wiring ground retaining screw securely.

Powertrain Control Module - Mounting
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Item Part Number Description
1 12A659 Powertrain Control Module Bracket
2 N606676-S2 Bolt
3 N807718-S36 Nut
4 01610 Dash Panel
5 12B523 Insulator
6 N621905-S2 Nut (2 Req'd) 
7 12A650 Powertrain Control Module
8 N808062-S36  Stud Bolt (2 Req'd) 
A -- Tighten to 8-12 N-m (71-106 Lb-In)
 

THROTTLE POSITION (TP) SENSOR

The throttle position sensor (TP sensor) is:

Removal

1. Disconnect battery ground cable.
2. Disconnect engine control sensor wiring from throttle position sensor (TP sensor).
3. Remove two throttle position sensor retaining screws.
4. Remove throttle position sensor.

Installation

1. CAUTION: Slide rotary tangs into position over throttle shaft blade, then rotate throttle position  sensor clockwise to installed position only. Failure to install the throttle position sensor in this  manner may result in damage to throttle position sensor or excessive idle speeds.
Note: This throttle position sensor is not adjustable. Install throttle position sensor. Make sure  rotary tangs on sensor are in proper alignment.
2. Secure throttle position sensor to throttle body with two retaining screws. Tighten to 2.8-3.8 N-m  (25-33 lb-in).
3. Connect engine control sensor wiring to throttle position sensor.
4. Connect battery ground cable.
 

MASS AIR FLOW (MAF) SENSOR

The mass air flow sensor (MAF sensor):

The mass air flow sensor hot wire sensing element and housing are calibrated as a unit and must be serviced as a complete assembly.

CAUTION:  The mass air flow sensor (MAF sensor) is a calibrated unit. Service hot wire engine element and housing as a complete assembly.

Removal

1. Disconnect battery ground cable.
2. Remove air cleaner outlet tube as described in.
3. Disconnect engine control sensor wiring connector from mass air flow sensor.
4. Remove four retaining nuts from air cleaner cover.
5. Carefully remove mass air flow sensor. Discard gasket.

Installation

1. Position mass air flow sensor with new gasket onto air cleaner cover.
2. Install four retaining nuts. Tighten to 8-12 N-m (71-106 lb-in).
3. Install air cleaner outlet tube.
4. Connect engine control sensor wiring connector to mass air flow sensor.
5. Connect battery ground cable.
6. Start engine and check for vacuum leaks.

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Item Part Number Description
1 9B659 Air Cleaner Outlet Tube
2 12B579 Mass Air Flow Sensor 
3 -- Gasket 
4 9600 Engine Air Cleaner
5 -- Nut (4 Req'd)
A -- Tighten to 8-12 N-m (71-106 Lb-In)
 

INTAKE AIR TEMPERATURE (IAT) SENSOR

The intake air temperature sensor (IAT sensor) changes resistance in response to intake air temperature. Resistance decreases as the surrounding air temperature increases, providing a signal to the powertrain control module (PCM) that indicates the temperature of the incoming intake air.

Note: The intake air temperature sensor (IAT sensor) is located in the engine air cleaner cover. When installing, use care not to damage plastic locking tabs.

Removal

1. Disconnect battery ground cable.
2. Disconnect engine control sensor wiring from intake air temperature sensor.
3. Turn intake air temperature sensor 90 degrees counterclockwise and remove from engine air cleaner  cover.
4. Inspect intake air temperature sensor O-ring for damage or deterioration and replace as necessary.

Installation

1. Follow removal procedure in reverse order.

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IDLE AIR CONTROL (IAC) VALVE

The idle air control valve (IAC valve):

Removal

1. Disconnect battery ground cable.
2. Disconnect the engine control sensor wiring from the idle air control valve (IAC valve) at the idle air  control valve electrical connector.
3. Remove the two idle air control valve retaining bolts.
4. Remove the idle air control valve and idle air control gasket (IAC gasket).

Installation

1. Note: If scraping is necessary, be careful not to damage idle air control valve gasket surface or drop  material into intake manifold or throttle body (depending upon application).  Clean idle air control valve gasket mating surfaces.
2. Follow removal procedure in reverse order.
3. Tighten the idle air control valve retaining bolts to 8-12 N-m (71-106 lb-in).


 

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

The engine coolant temperature sensor (ECT sensor) changes resistance in response to the temperature of the engine coolant. Resistance decreases as the surrounding temperature increases, providing a signal to the powertrain control module (PCM) that indicates the temperature of the engine coolant.

Removal

1. Drain engine cooling system.
2. Disconnect battery ground cable.
3. Remove the engine intake air resonator.
4. Disconnect engine control sensor wiring from engine coolant temperature sensor .
5. Remove engine coolant temperature sensor.

Installation

1. Follow removal procedure in reverse order.
2. Tighten engine coolant temperature sensor to 14-19 N-m (11-14 lb-ft).
3. Install the engine intake air resonator.


 

HEATED OXYGEN SENSOR (HO2S)

The heated oxygen sensors (HO2S):