Issue Summary:
- 1995-2005 Hyundais may exhibit complaints including a flare on the 2-3 shift, no lockup application, no fourth gear, 1-2 shift only and harsh garage shifts.
- A Hyundai with the A4BF1 has the MIL on with no apparent drivability complaints and the transmission is not in limp mode, but codes P0743 and P0747 are stored.
- A Toyota vehicle with a 540-H or 540-E transaxle may have no reverse, and no engine braking in Manual 2 or Manual 1.
- Mitsubishi vehicles with R4A51/V4A51-series transmissions may exhibit poor shift quality or a flared 2-3 upshift after overhaul.
All Hyundai models built from 1995 to 2005 may exhibit complaints including a flare on the 2-3 shift, no lockup application, no fourth gear, 1-2 shift only and harsh garage shifts.
In addition, codes P0711, P0712 and/or P0713 concerning ATF temperature sensor faults may be stored.
A malfunction of the transmission-fluid-temperature (TFT) sensor resulting in storage of any of the codes mentioned can cause the complaints listed.
Following is the computer strategy corresponding to the codes listed:
P0711 – TFT performance malfunction
The malfunction indicator lamp (MIL) will be turned on with P0700 stored, indicating that the TCM has requested from the PCM that the MIL be turned on.
P0712 – TFT circuit shorted
MIL is turned on. Flare on the 2-3 shift.
P0713 – TFT circuit open
MIL is turned on. Harsh garage shifts, damper clutch does not engage, no 4th-gear command, stays in 3rd, 2nd-gear hold (1-2 shift only).
Replace TFT sensor or repair sensor wiring. Figure 1 shows the location of the ATF-temperature sensor for the A4BF1, A4AF2, A4AF3 and A4BF2.
Figure 2 shows the location of the ATF-temperature sensor for the F4A40/50 series.
TFT sensor for:
- 1995-2005 Accent; 1996-2000 Elantra; 1996-2000 Tiburon A4A/B series . . . . . . . . . . . . . . . . .46386-22600
TFT sensor for:
- 1999-2005 Sonata; 2001-2005 Elantra; 2001-2005 Santa Fe; 2001-2005 XG300/350; 2003-2005 Tiburon; 2005 Tucson F4A40/50 series . . . . . . . . . . . . . . . . . . .46386-39050
The vehicle has the MIL on with no apparent drivability complaints, and the transmission is NOT in limp mode. However, scanning the TCM for codes reveals that P0743, TCC-solenoid circuit fault, and P0747, pressure-control-solenoid A circuit fault, are stored.
Solenoid-circuit checks revealed no problems, and checks of system voltage and TCM power and ground also indicated no faults. The TCM was not considered for replacement, as the transmission was not in limp mode.
Note: Although this was a 1997 Hyundai Tiburon, this could conceivably occur with virtually any vehicle using the A4BF1.
A spare “known good” set of solenoids was connected to the vehicle harness, and ground was provided for the solenoids directly to the negative battery cable.
The codes were cleared and did not return. As a test, these solenoids were installed into the transmission and the codes immediately returned.
A cable was attached directly to the negative battery cable at the battery (see Figure 3), with the other end attached to the transmission case (see Figure 4).
Obviously there is a ground problem somewhere in this vehicle, but finding it would have consumed too much time.
Before or after overhaul, Toyota vehicles equipped with the 540-H or 540-E transaxle may exhibit a no-reverse condition, and no engine braking when the driver selects Manual 2 or Manual 1.
The cause may be that the inner O-ring in the over-drive direct-clutch piston is blown out, causing a leak in the OD direct-clutch circuit. The reason for the piston-seal blowout may be excessive wear in the pressure-regulator boost sleeve resulting in high pressure in the reverse circuit, bowing the piston in the center and blowing out the piston seal.
Note: ATSG also has heard complaints of some aftermarket filters having defective cork gaskets causing numerous holes in the spacer plate to be plugged, causing very high pressure and the same failure.
To correct this condition, replace the boost sleeve with one from Toyota or Sonnax (see figures 5 and 6).
Renew the piston seals in the OD direct-clutch drum (refer to Figure 7). Verify that the piston is not warped by checking with a straightedge as shown in Figure 7.
- 540-H boost sleeve (Toyota number) . . . .35417-32031
- 540-E boost sleeve (Toyota number) . . . .35417-32021
- 3.0L Sonnax boost valve and sleeve (high-ratio) . . . . . . . . .89031-01K
- 2.5L Sonnax boost valve and sleeve (low-ratio) . . . . . . . . . .89031-02K
Vehicles equipped with the R4A51/V4A51-series transmissions may exhibit poor shift quality or a flared 2-3 upshift after overhaul, typically after a planetary failure.
The cause may be that the pressure-regulator spring may be losing its tension or is shrinking from the extreme heat of the planetary failure.
Note: The planetary failure is usually due to failure of the torque-converter clutch, resulting in clogging of the cooler and a loss of lubrication.
To correct this condition, first verify what the base pressures are on the underdrive clutch and the low/reverse brake in the Drive position. Figure 8 shows line-pressure specifications.
If the pressure is below 147-152 psi in both ports, remove the valve body and inspect the pressure-regulator valve for sticking in its bore. If it is free, refer to the specs in Figure 9 to verify the adjustment of the spring.
If the spring is shorter than 1.760 inches, turn the adjustable bore plug shown in figures 9 and 10 counterclockwise to increase the base line pressure, and replace the pressure-regulator-valve spring if necessary.
June 2008 Issue
Volume 25, No. 6
- Hyundai A4A/B & F4A40/50-Series Transmissions: 2-3 Flare, No Fourth, No Lockup
- Hyundai A4BF1: False Codes
- Toyota 540-E/540-H: No Reverse, No Engine Braking
- Mitsubishi R4A51/V4A51: Poor Shift Quality/2-3 Flare