Code 44: A Combination Of At Control Abnormal

WARNING: This page is about a different car, the 2001 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.

DIAGNOSIS:

Combination of AT control faults

TROUBLE SYMPTOM:

ABS does not operate.

WIRING DIAGRAM:

Fig 1: Wiring Diagram

8U1: CHECK SPECIFICATIONS OF THE ABSCM & H/U.
Check specifications of the mark to the ABSCM & H/U.

Fig 2: Identifying Mark On ABSCM & H/U

Fig 3: Specifications On Mark On ABSCM & H/U

CHECK: Is an ABSCM & H/U for AT model installed on a MT model?
1. YES: Replace ABSCM & H/U, see ABS CONTROL MODULE AND HYDRAULIC CONTROL UNIT (ABSCM & H/U) .
2. NO: Go to step 8U2.
8U2: CHECK GROUND SHORT OF HARNESS.
1. Turn ignition switch to OFF.
2. Disconnect the two connectors from TCM.
3. Disconnect connector from ABSCM & H/U.
4. Measure resistance between ABSCM & H/U connector and chassis ground
Connector & terminal
1. (F49) No. 3 - Chassis ground:
Fig 4: Measuring Resistance Between ABSCM & H/U Connector & Chassis Ground

CHECK: Is the resistance more than 1 Mohm?
1. YES: Go to step 8U3.
2. NO: Repair harness between TCM and ABSCM & H/U.
8U3: CHECK BATTERY SHORT OF HARNESS.
Measure voltage between ABSCM & H/U connector and chassis ground.

Connector & Terminal
1. (F49) No. 3 (+) - Chassis ground (-):
Fig 5: Measuring Voltage Between ABSCM & H/U Connector & Chassis Ground

CHECK: Is the voltage less than 1 V?
1. YES: Go to step 8U4.
2. NO: Repair harness between TCM and ABSCM & H/U.
8U4: CHECK BATTERY SHORT OF HARNESS.
1. Turn ignition switch to ON.
2. Measure voltage between ABSCM & H/U connector and chassis ground.
Connector & terminal
1. (F49) No. 3 (+) - Chassis ground (-):
Fig 6: Measuring Voltage Between ABSCM & H/U Connector & Chassis Ground

CHECK: Is the voltage less than 1 V?
1. YES: Go to step 8U5.
2. NO: Repair harness between TCM and ABSCM & H/U.
8U5: CHECK TCM.
1. Turn ignition switch to OFF.
2. Connect all connectors to TCM.
3. Turn ignition switch to ON.
4. Measure voltage between TCM connector terminal and chassis ground.
Connector & terminal
1. (B54) No. 19 (+) - Chassis ground (-):
Fig 7: Measuring Voltage Between TCM Connector Terminal & Chassis Ground

CHECK: Is the voltage between 6 and 15 V?
1. YES: Go to step 8U7: CHECK OPEN CIRCUIT OF HARNESS .
2. NO: Go to step 8U6.
8U6: CHECK AT.
CHECK: Is the AT functioning normally?
1. YES: Replace TCM. See TRANSMISSION CONTROL MODULE (TCM) .
2. NO: Repair AT.
8U7: CHECK OPEN CIRCUIT OF HARNESS.
Measure voltage between ABSCM & H/U connector and chassis ground.

Connector & terminal
1. (F49) No. 3 (+) - Chassis ground (-):
2. (F49) No. 31 (+) - Chassis ground (-):
Fig 8: Measuring Voltage Between ABSCM & H/U Connector & Chassis Ground

CHECK: Is the voltage between 5.5 and 15 V?
1. YES: Go to step 8U8.
2. NO: Repair harness/connector between TCM and ABSCM & H/U.
8U8: CHECK POOR CONTACT IN CONNECTORS.
CHECK: Is there poor contact in connectors between TCM and ABSCM & H/U?
1. YES: Repair connector.
2. NO: Go to step 8U9.
8U9: CHECK ABSCM & H/U.
1. Turn ignition switch to OFF.
2. Connect all connectors.
3. Erase the memory.
4. Perform inspection mode.
5. Read out the trouble code.
CHECK: Is the same trouble code as in the current diagnosis still being output?
1. YES: Replace ABSCM & H/U, see ABS CONTROL MODULE AND HYDRAULIC CONTROL UNIT (ABSCM & H/U) .
2. NO: Go to step 8U10.
8U10: CHECK ANY OTHER TROUBLE CODES APPEARANCE.
CHECK: Are other trouble codes being output?
1. YES: Proceed with the diagnosis corresponding to the trouble code.
2. NO: A temporary poor contact.