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Home >> Volvo >> 1995 >> 850 L5-2.4L VIN 55 B5254S >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> AT / DTC Codes (Transmission Control Module) >> DTC 131

DTC 131



EAJ. Code 1-3-1

1-3-1 Break or short-circuit to ground in solenoid STH circuit

DTC information

Conditions for DTC






Solenoid STH controls the transmission system pressure. The solenoid is controlled by an integral amplifier (driver stage) on the output of the transmission control module (TCM). The TCM uses the driver stage to regulate the current supplied to the solenoid. A low amperage gives a high system pressure and a high amperage (approx. 1 A) gives a low system pressure. The amperage of this current is affected primarily by the throttle position. If the TCM registers a break on the solenoid STH circuit or the circuit is short-circuited to ground so there is too little current in the circuit, DTC 1-3-1 is set. Solenoid STH then cannot control the system pressure.

Substitution value

Control Modules GROUP I:
No substitution value

Control Modules GROUP II:
The transmission control module (TCM) "Emergency mode II" program is initiated.

Defect cause

- Break in the control signal wiring or signal wiring.
- Short circuit to ground in the control signal wiring or signal wiring.
- Incorrect supply voltage to the system
- Malfunction in solenoid STH
- Contact resistance in connections.

Fault symptom

- Rough gear shifting due to maximum system pressure in the transmission
- No Lock-Up operational.

- Fault-tracing starts with EAJ1.



EAJ1

Checking solenoid STH






- Ignition ON.
- Set gearshift selector to position P.

Check solenoid STH using Diagnostic Test Mode 4. Use a stethoscope to hear if the solenoid is operating.


NOTE: The solenoid only clicks twice - when stopping and when starting. So listen carefully.


If solenoid is operating:
- Intermittent fault. Fault-tracing as per EAJ4.

If the solenoid is not operating:
- Checking voltage drop over signal ground (SG) and power ground (PG) EAJ2.



EAJ2

Checking voltage drop over signal ground (SG) and power ground (PG)






- Ignition OFF
- Connect test box and check ground points as per GB1-GB2
- Connect TCM
- Ignition ON.
- Turn on as many power consuming items as possible. Use a voltmeter to measure between #20 (#A20) and #29 (#A29) on the test box.

The voltmeter should read less than 0.6 V.






If reading is OK:
- Checking voltage drop over signal ground EAJ3.
- Check ground points 31/32 and 31/33 the cables between the ground points and the TCM, and the TCM connectors for a break as per FA2 and contact resistance and oxidation as per FA6. FA. Checking Wiring and Connections
Then continue with: Checking voltage drop over signal ground EAJ3.



EAJ3

Checking voltage drop over signal ground






- Ignition OFF
- Test box connected
- Connect a test box to the engine control module ECM (MFI Fenix 5.2, LH 3.2, or Motronic 4.3).
- Control modules connected
- Ignition ON.
- Turn on as many power consuming items as possible.

Connect a voltmeter between the transmission test box #20 (#A20) and the ECM module test box:






- for Fenix 5,2 MFI control module: #42 (#A42) (signal ground, control module)
- LH 3,2 MFI control module: #20 (#A20) (signal ground, control module)
- Motronic 4,3 MFI control module: #42 (#A42) (signal ground, control module)

The voltmeter should read less than 0.10 V.

If reading is OK:
- Checking supply voltage (15 supply) EAJ4.

If reading is incorrect:
- Check ground point 31/33, cables between the ground point and the TCM and MFI module for contact resistance and oxidation as per FA6. FA. Checking Wiring and Connections
Then continue with: Checking supply voltage (15 supply) EAJ4.



EAJ4

Checking supply voltage (15 supply)







- Ignition ON.

Use a voltmeter to measure between #30 (#A30) and #29 (#A29) on the test box.
The voltmeter should register approx. battery voltage.

If reading is OK:
- Checking supply voltage (30 supply) EAJ5.

If reading is incorrect:
- Check the cable between fuse 11/1 and the TCM #A30 for breaks as per FA2. FA. Checking Wiring and Connections





EAJ5

Checking supply voltage (30 supply)






- Ignition ON.

Use a voltmeter to measure between #10 (#A1O) and #20 (#A20) on the test box.
The voltmeter should register approx. battery voltage.

If reading is OK:
- Checking resistance in solenoid STH circuit EAJ6.

If reading is incorrect:
-^ Check the cable between the positive terminal on the battery and TCM #A10 for breaks as per FA2. FA. Checking Wiring and Connections



EAJ6

Checking resistance in solenoid STH circuit






- Ignition OFF
- Disconnect TCM

Use a ohmmeter to measure between #22 (#A22) and #23 (#A23) on the test box.
The ohmmeter should read 2-6 Ohms.

If reading is OK:
- Checking solenoid STH circuit, short-circuit to ground EAJ11.

If reading is incorrect:
- Checking resistance in solenoid STH circuit in the transmission EAJ7.



EAJ7

Checking resistance in solenoid STH circuit in the transmission






- Ignition OFF
- Remove the air cleaner (AC) housing to access the transmission connector
- Disconnect the transmission connector.

Connect an ohmmeter between the transmission connector terminals 24 and 25 (transmission side).

The ohmmeter should read 2-6 Ohms.

If reading is OK:
- Checking resistance in control signal wiring EAJ9.

If reading is incorrect:
- Checking resistance in solenoid STH EAJ8.


EAJ8

Checking resistance in solenoid STH






- Ignition OFF
- Open the control system, as per R1-R13.
- Disconnect solenoid STH.

Connect ohmmeter between the pins in the solenoid connector.
The ohmmeter should read 2-6 Ohms.

If reading is OK:
- Check the wiring between solenoid STH and the transmission connector terminals 24 and 25 for break as per FA2. FA. Checking Wiring and Connections

If reading is incorrect:
- Replace transmission control system as per R1-R14.



EAJ9

Checking resistance in the control signal wiring






- Ignition OFF
- Disconnect transmission connector.

Connect an ohmmeter between the transmission connector terminal 24 (TCM side) and #22 (#A22) on the test box.

The ohmmeter should read approx. 0 Ohms.






If reading is OK:
- Checking the signal wiring resistance EAJ1O.

If reading is incorrect:
- Check the cable between the transmission connector terminal 24 and TCM #A22 for breaks in the circuit as per FA2. FA. Checking Wiring and Connections



EAJ1O

Checking signal wiring resistance






- Ignition OFF
- Disconnect transmission connector.

Connect an ohmmeter between the transmission connector terminal 25 (TCM side) and #23 (#A23) on the test box.

The ohmmeter should read approx. 0 Ohms.






If reading is OK:
- The DTC was set because of poor contact in the TCM or transmission connectors. Check the connectors for loose connections as per FA5, and contact resistance and oxidation as per FA6. FA. Checking Wiring and Connections

If reading is incorrect:
- Check the cable between the transmission connector terminal 25 and TCM #A23 for breaks in the circuit as per FA2.



EAJ11

Checking solenoid STH circuit for short-circuit to ground






- Ignition OFF
- TCM disconnected.

Use an ohmmeter to measure between the transmission housing and #22 (#A22) on the test box.

The ohmmeter should read infinite resistance.

If reading is OK:
- The DTC was set because of poor contact in the TCM connector. Correct the fault in the connectors for the transmission and the transmission control module (TCM) after checking for loose connections as per FA5, and contact resistance and oxidation as per FA6. FA. Checking Wiring and Connections

If reading is incorrect:
- Checking solenoid STH circuit in the transmission, break to ground EAJ12.



EAJ12

Checking solenoid STH circuit in the transmission, break to ground EAJ12.






- Ignition OFF
- Remove the air cleaner (AC) housing to access the transmission connector
- Disconnect the transmission connector.

Connect an ohmmeter between the transmission connector terminal 24 (transmission side) and the transmission housing.
The ohmmeter should read infinite resistance.

If reading is OK:
- Check signal wiring resistance to ground EAJ14.

If reading is incorrect:
- Checking solenoid STH, resistance to ground EAJ13.



EAJ13

Checking solenoid STH, resistance to ground






- Ignition OFF
- Open the control system, as per R1-R13.
- Disconnect solenoid STH.

Connect an ohmmeter between one of the pins in the solenoid connector and the transmission housing.
The ohmmeter should read infinite resistance.

If reading is OK:
- Check wiring between the driving solenoid STH and transmission connector terminals 24 and 25 for short circuit to ground as per FA3. FA. Checking Wiring and Connections

If reading is incorrect:
- Replace transmission control system as per R1-R14.


EAJ14

Checking signal wiring resistance to ground






- Ignition OFF
- TCM disconnected.
- Disconnect transmission connector.

Use an ohmmeter to measure between the transmission housing and #22 (#A22) on the test box.
The ohmmeter should read infinite resistance.

If reading is OK:
- Check the cable between the transmission connector terminal 25 and the TCM #A23 for short circuit to ground as per FA3. FA. Checking Wiring and Connections

If reading is incorrect:
- Check the cable between the transmission connector terminal 24 and the TCM #A22 for short circuit to ground as per FA3.



EAJ15

Intermittent Fault.

Checking wiring and connections






- Check the connectors for the transmission and the transmission control module (TCM) for loose connections as per FA5, and contact resistance and oxidation as per FA6. FA. Checking Wiring and Connections

- Check the cables between solenoid STH and TCM #A22 and #A23 for intermittent break as per FA2, and for intermittent short circuit to ground as per FA3.









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