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General Procedures > < Transaxle Electronic Control System

Fiesta 2002.25 (11.2001-)

Automatic Transmission/Transaxle - Vehicles With: 4-Speed Automatic Transmission (AW81-40) - Automatic Transaxle Fiesta 2002.25 (11/2001-)
Diagnosis and Testing

Special Tool(s)

Hydraulic Pressure Gauge (0 - 60 bar)

307-201

Adapter for 307-201

307-201-01
General Equipment
Worldwide Diagnostic System (WDS)

Inspection and Verification

  1. Verify the customer concern.
  1. Visually inspect for obvious signs of mechanical or electrical damage.

    Visual Inspection Chart

    Mechanical Electrical
    • Damaged shift mechanism
    • Transaxle fluid leaks
    • Damaged transaxle casing
    • Fuse(s)
    • Electrical connector(s)
  1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
  1. If the cause is not visually evident, verify the symptom and refer to the Diagnostic Trouble Code Chart.

Diagnostic Trouble Code Chart

Diagnostic Trouble Code Charts

Symptom Possible Sources Action
A207 Checksum error
*
Transmission control module (TCM) .
*
Circuit(s).
*
REFER to WDS.
E516 CAN bus OFF sensor error
*
CAN bus.
*
REFER to WDS.
D900 CAN bus no communication error
*
CAN bus.
*
REFER to WDS.
P0706 Transmission range (TR) sensor error
*
Inhibitor switch.
*
Inhibitor switch circuit(s).
*
REFER to WDS.
P0707 Transmission range (TR) sensor circuit low input
*
Inhibitor switch.
*
Inhibitor switch circuit(s).
*
REFER to WDS.
P0712 Transmission fluid temperature circuit - low input
*
Transmission fluid temperature sensor.
*
Circuit(s).
*
REFER to WDS.
P0713 Transmission fluid temperature circuit - high input
*
Transmission fluid temperature sensor.
*
Circuit(s).
*
REFER to WDS.
P0717 Input speed sensor circuit no signal
*
Input speed sensor.
*
Circuit(s).
*
REFER to WDS.
P0722 Vehicle speed sensor (VSS) circuit no signal
*
Vehicle speed sensor (VSS).
*
Circuit(s).
*
REFER to WDS.
P0740 Torque converter clutch solenoid failure
*
Lock-up duty solenoid.
*
Circuit(s).
*
REFER to WDS.
P0741 Torque converter clutch (TCC) system.
*
TCC system stuck off.
*
REFER to WDS.
P0742 Torque converter clutch (TCC) system.
*
TCC system stuck on.
*
Circuit(s).
*
REFER to WDS.
P0743 Torque converter clutch solenoid failure
*
Lock-up duty solenoid.
*
Circuit(s).
*
REFER to WDS.
P0727 Engine revolution speed error
*
Powertrain control module (PCM).
*
Circuit(s).
*
REFER to WDS.
P1746 Pressure control solenoid A open circuit
*
Line pressure control solenoid.
*
Circuit(s).
*
REFER to WDS.
P1747 Pressure control solenoid A short circuit
*
Line pressure control solenoid.
*
Circuit(s).
*
REFER to WDS.
P0972 Shift solenoid A performance
*
Shift solenoid A open circuit.
*
Circuit(s).
*
Internal mechanical/hydraulic failure.
*
REFER to WDS.
P0973 Shift solenoid A electrical
*
Shift solenoid A short circuit.
*
Circuit(s).
*
REFER to WDS.
P0974 Shift solenoid A electrical
*
Shift solenoid A.
*
Circuit(s).
*
REFER to WDS.
P0975 Shift solenoid B performance
*
Shift solenoid B.
*
Circuit(s).
*
Internal mechanical/hydraulic failure.
*
REFER to WDS.
P0976 Shift solenoid B
*
Shift solenoid B short circuit.
*
Circuit(s).
*
REFER to WDS.
P0977 Shift solenoid B
*
Shift solenoid B open circuit.
*
Circuit(s).
*
REFER to WDS.
P0787 Timing solenoid electrical
*
Timing solenoid short circuit.
*
Circuit(s).
*
REFER to WDS.
P0788 Timing solenoid electrical
*
Timing solenoid open circuit.
*
Circuit(s).
*
REFER to WDS.
P0115 Engine coolant signal error
*
Reported engine failure.
*
REFER to WDS.
P1719 Engine torque signal error
*
Reported engine failure.
*
REFER to WDS.
P1783 Transmission over temperature condition
*
Temperature sensor failure.
*
REFER to WDS.
C1750 Accelerator pedal position signal malfunction
*
Accelerator pedal position sensor.
*
REFER to WDS.
U2516 CAN bus off transmit error
*
CAN bus.
*
REFER to WDS.
U1900 CAN Communication bus fault error
*
CAN bus.
*
REFER to WDS.
5750 Throttle open malfunction
*
CAN bus.
*
REFER to WDS.

Line Pressure Test

CAUTION:
CAUTION:Carry out the line pressure test before carrying out the stall speed test. If line pressure is low at idle, do not carry out the stall speed test or further transaxle damage will occur.
CAUTION:
CAUTION:Do not maintain wide open throttle (WOT) in any range for more than five seconds.
CAUTION:
CAUTION:After testing each of the following ranges 'D' (DRIVE) and 'R' (REVERSE), move the selector lever to 'N' (NEUTRAL) and run the engine at 1000 rpm for approximately 1 minute to allow the torque converter to cool.
NOTE:
NOTE:Make sure that the self test and electrical repairs have been carried out, or test results may be incorrect.

  1. Connect the special tools to the line pressure test point.
  1. Start the engine and check the line pressures. Refer to the line pressure chart to determine if line pressure is within specification.
  1. If the line pressure is not within specification, refer to the line pressure diagnosis chart.

Line Pressure Chart

Range Idle Stall
Mpa bar Mpa bar
D 0.37 - 0.41 3.82 - 4.11 1.15 - 1.27 11.5 - 12.7
R 0.59 - 0.68 5.88 - 6.76 1.58 - 1.83 15.88 - 18.24

Line Pressure Diagnosis Chart

Test Results Possible Source
Higher than specification in 'D' (DRIVE) and 'R' (REVERSE) Pressure control solenoid inoperative or open wire harness.
Pressure regulator valve sticking.
Lower than specification in 'D' (DRIVE) and 'R' (REVERSE) Pressure control solenoid inoperative or open wire harness.
Pressure regulator valve sticking.
Worn oil pump.
Oil strainer blocked.
Fluid leak from each clutch hydraulic circuit.
Lower than specification in 'D' (DRIVE) Drive hydraulic circuit failure.
Forward clutch failure.
Lower than specification in 'R' (REVERSE) Reverse hydraulic circuit failure.
Reverse clutch failure.
First and reverse brake failure.

Stall Speed Test

This test checks the operation of the following components:

  • torque converter
  • forward clutch
  • low one way clutch assembly
  • engine performance
WARNING:
WARNING:Apply the parking brake firmly while carrying out each stall test.
WARNING:
WARNING:Apply the foot brake firmly while carrying out each stall test.
CAUTION:
CAUTION:Always carry out the line pressure test before carrying out the stall speed test. If the line pressure is low at idle, do not carry out the stall speed test or further transaxle damage will occur.
CAUTION:
CAUTION:After testing each of the following ranges 'D' (DRIVE) and 'R' (REVERSE), move the selector lever to 'N' (NEUTRAL) and run the engine at 1000 rpm for approximately one minute to allow the torque converter to cool.
CAUTION:
CAUTION:Do not maintain wide open throttle (WOT) in any range for more than five seconds.
CAUTION:
CAUTION:If the engine speed (rpm) recorded by the tachometer exceeds maximum specified rpm, release the accelerator pedal immediately. Clutch or band slippage is indicated.
NOTE:
NOTE:The stall speed test should be carried out with the engine and transaxle at normal operating temperatures (50°C to 80°C).
NOTE:
NOTE:Prolonged use of this procedure may set DTC P0712. After carrying out the stall speed test, run the OBD test and clear the DTCs.
  1. Connect a tachometer to the engine.
  1. Press the accelerator pedal to the floor WOT in each selected range. Record the rpm reached in each selected range and refer to the stall speed chart.
  1. If the stall speed is not within specification, refer to the stall speed diagnosis chart.

Stall Speed Chart

Engine 1.6L Speed (rpm)
'D' (DRIVE) 2500 ± 150
'R' (REVERSE) 2420 ± 150

Stall Speed Diagnosis Chart

Test Results Possible Source
Lower than specification in 'D' (DRIVE) and 'R' (REVERSE) Low engine power.
Torque converter one-way clutch failure.
Higher than specification in 'D' (DRIVE) Pressure control solenoid inoperative.
Pressure regulator valve sticking.
Forward clutch failure (slipping).
One-way clutch No.2 failure.
Higher than specification in 'R' (REVERSE) Pressure control solenoid inoperative.
Pressure regulator valve sticking.
Reverse clutch failure (slipping).
First and reverse brake failure (slipping).
Lower than specification in 'D' (DRIVE) Drive hydraulic circuit failure.
Forward clutch failure.
Lower than specification in 'R' (REVERSE) Pressure control solenoid inoperative.
Pressure regulator valve sticking.
Worn oil pump.
Oil strainer blocked.
Fluid leak from each clutch hydraulic circuit.

Time Lag Test

Time lag is the time between moving the selector lever from 'N' (NEUTRAL) to 'D' (DRIVE) or 'N' (NEUTRAL) to 'R' (REVERSE). With the parking brake applied the vehicle must not move if the selector lever is moved from 'N' (NEUTRAL) to 'D' (DRIVE) or 'N' (NEUTRAL) to 'R' (REVERSE). Drive is engaged when the vehicle starts to rise.

WARNING:
WARNING:Apply the parking brake firmly while carrying out each test.
CAUTION:
CAUTION:After testing each of the following ranges 'D' (DRIVE) and 'R' (REVERSE), move the selector lever to 'N' (NEUTRAL) and run the engine at 1000 rpm for approximately 1 minute to allow the torque converter to cool.
  1. Using a suitable stop watch, measure the time lag three times and calculate the average time. Record the time lag and refer to the time lag chart.
  1. If the time lag is not within specification, refer to the time lag diagnosis chart.

Time Lag Chart

Range Time
'N' (NEUTRAL) to 'D' (DRIVE) less than 1.0 seconds
'N' (NEUTRAL) to 'R' (REVERSE) less than 1.2 seconds

Time Lag Diagnosis Chart

Test Results Possible Source
Lower than specification in 'N' (NEUTRAL) to 'D' (DRIVE) Pressure control solenoid inoperative.
Pressure regulator valve sticking.
Forward clutch failure (slipping).
Timing solenoid failure.
Drive hydraulic circuit failure.
Lower than specification in 'N' (NEUTRAL) to 'R' (REVERSE) Pressure control solenoid inoperative.
Pressure regulator valve sticking.
Reverse clutch failure (slipping).
First and reverse brake failure (slipping).
Reverse hydraulic circuit failure.

General Procedures > < Transaxle Electronic Control System