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Shawn
Shawn, Auto Service Technician
Category: Ford
Satisfied Customers: 3756
Experience:  16 years experience Ford,Nissan and Honda dealership in all areas
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1998 Ford escort zx2: DOHC..2.0L-Automatic Transmission)..Malfunction

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I have a 1998 Ford escort zx2 (DOHC 2.0L-Automatic Transmission) and P0750 keeps popping up on the OBD. So, shift solenoind A Malfunction. Do you have any ideas on what to look for when trying to fix this problem? My hubby checked it and the transmission itself is shifting into all gears fine, but reverse will not work??? What should I do to fix this?

HiCustomer

 

Thank you for asking your question on JustAnswer.

 

 

The most common cause of the DTC (Diagnostic Trouble Code) PO750, is a defective shift solenoid, which is located in the Main Control Valve Body-Assembly, (FOR INSTRUCTIONS CLICK HERE).

CLICK HERE FOR REMOVAL INSTRUCTIONS

In order to properly diagnose you will a NGS (New Generation Star) scan tool or equivalent AND A dvom (DIGITAL VOLT OHM METER), see below. Hope this helps you out.

 

Pinpoint Test A - Shift Solenoid

DTC List:

P0781, P0782, P0783, P1731, P1732, P1733 - Shift errors.

P0750, P0755, P0760 - Solenoid circuit failures.

P0751, P1751 - Shift solenoid number 1 malfunction.

P0756, P1756 - Shift solenoid number 2 malfunction.

P0761, P1761 - Shift solenoid number 3 malfunction.

This pinpoint test is intended to diagnose the shift solenoids electrical system only. To prevent replacement of good components, be aware that the following areas may be at fault:

  • Engine.
    • Performance, cooling, brakes.
  • Electrical.
    • Battery, input sensors, wiring harnesses.
  • Transmission.
    • Internal transmission components, linkages, cooling.

This pinpoint test is intended to diagnose the following components:

  • Transmission wiring harness, SS1, SS2, SS3.
  • Powertrain control module.



Solenoid Operation Chart
Gearshift Lever PositionPCM Commanded GearSolenoids
SS1SS2SS3
P/N-OFFOFFON
R-OFFOFFOFF
(D)1OFFONOFF
(D)2ONONON
(D)3 (Below 26 km/h [16 mph])OFFOFFOFF
(D)3 (Above 26 km/h [16 mph])ONOFFOFF
(D)4ONOFFON
D1OFFONON
D2ONONON
D3 (Below 26 km/h [16 mph])OFFOFFOFF
D3 (Above 26 km/h [16 mph])ONOFFOFF
L1OFFONOFF
L2* (Below 110 km/h [68 mph])ONONOFF
L2* (Above 110 km/h [68 mph])ONOFFOFF
* Overspeed protection only.

PINPOINT TEST A: SHIFT SOLENOID
CONDITIONSDETAILS/RESULTS/ACTIONS
A1 ELECTRONIC DIAGNOSTICS
Check to make sure the transmission harness connector is fully seated, terminals are engaged in connector and in good condition before proceeding.
CONNECT NGS
Diagnostic Data Link
PCM
Active Command Modes
Trigger the PCM active command OUTPUT TEST MODE ALL ON.

  • Does the vehicle enter OUTPUT TEST MODE?
Yes REMAIN in OUTPUT TEST MODE. GO to A2 .
No PRESS START. If the vehicle does not enter the OTM, REFER to Powertrain Control/Emissions Diagnosis (PC/ED) manual Manual Output Test Mode NOT FUNCTIONING in Section 5A, (Pinpoint Test MB).
A2 CHECK THE ELECTRICAL SIGNAL OPERATION
NOTE: The 8-pin transmission connector refers to the connector at the base of the transmission.
DISCONNECT 8-Pin Transmission ConnectorCAUTION: Do not pry on the connector. This will damage the connector and could result in a transmission concern. Pull up on the connector harness.
    Disconnect the 8-pin transmission connector.
Use a mirror to inspect both ends of the connector for damage or pushed out pins, corrosion, loose wires and missing or damaged seals.
graphic
Measure the voltage between appropriate solenoid circuit at the 8-pin transmission connector, pin 3 (O/GN), pin 4 (LG/BL), or pin 8 (PK/BK), and ground.
While observing the Volt Ohm Meter, press start and stop to cycle solenoid output ON and OFF.

  • Does the suspect solenoid output voltage change at least 0.2 volts?
Yes GO to A5.
No GO to A3.
A3 CHECK THE CONTINUITY OF THE SOLENOID SIGNAL CIRCUITS
DISCONNECT PCM C212Inspect for damaged or pushed out pins, corrosion or loose wires.
Connect the EEC5 104 Pin Breakout Box and leave the PCM disconnected.
graphicMeasure the resistance of the appropriate solenoid circuit between the powertrain control module (PCM) signal test pin 1, 27, or 53 at the breakout box and the signal pin 3 (O/GN), pin 4 (LG/BL), or pin 8 (PK/BK) at the 8-pin transmission connector.

  • Is each resistance less than 5 ohms?
Yes GO to A4.
No REPAIR the open circuit(s). REMOVE the breakout box. RECONNECT all of the components. REPEAT the Quick Tests.
A4 CHECK THE SOLENOID HARNESS FOR SHORT TO POWER AND GROUND
graphic
Measure the resistance of the appropriate solenoid circuit between the PCM signal output test pin 1, 27, or 53 and test pins 71 and 97 at the breakout box.
graphic
Measure the resistance of the appropriate solenoid circuit between the PCM signal output test pin 1, 27, or 53 and test pins 51 and 91 at the breakout box, and ground.

  • Are the resistances greater than 10,000 ohms?
Yes REPLACE PCM; TEST the vehicle for normal operation.
No REPAIR the short circuit(s). REMOVE the breakout box. RECONNECT all of the components. REPEAT the Quick Tests.
A5 CHECK THE RESISTANCE OF THE SOLENOID/HARNESS


RECONNECT 8-Pin Transmission Connector
DISCONNECT Transmission C191
graphic
Measure the resistance of the appropriate solenoid circuit between the transmission C191F-3 (BK/BR), C191F-4 (PK/BL), and C191F-8 (GY/BK), and ground.
Record the resistance. The resistance should be between 12 and 20 ohms.

  • Is the resistance for each solenoid between 12 and 20 ohms?
Yes GO to Diagnosis By Symptom. REPAIR or REPLACE as necessary.
No REPLACE the main control valve body.

 

 


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