P1857

DIAGNOSTIC TROUBLE CODES P1857 AND P1858
SHIFT SOLENOID, SOLENOID S2 (2-3),
INPUT FROM TCM TOO LOW/SHORT CIRCUIT TO GROUND (P1857)
OUTPUT FROM TCM TOO HIGH/OPEN CIRCUIT OR SHORT CIRCUIT TO BATTERY POSITIVE VOLTAGE (P1853)

Fault Symptom.
Warning lamp CHECK GEARBOX lit. System's emergency program in operation.
P1857: Gear shifting impossible.
P1858: Gear shifting cannot take place with solenoid S2 and transmission only operates in fourth gear.

Conditions.
P1857: Short circuit to ground when solenoid is activated. Solenoid is activated in gear positions P, R and N or if the car is run in gear positions D or 3 in first or second gears.
P1853: Short circuit to battery positive voltage when the solenoid is not activated. Solenoid not activated if the car is run in gear positions D or 3 in third or fourth gears.

Diagnostic Procedure.
1. Connect ISAT scan tool to the car's data link connector. Activate solenoid 2 by initiating SOLENOID 2 in ISAT menu ACTIVATE. The solenoid is checked with a frequency of 1 Hz, i.e. switched on and off once every second. Listen for a clicking sound in the solenoid.

If the solenoid clicks, go to step 10.

If the solenoid does not click, go to step 2.





2. If you are not entirely sure, continue with ISAT scan tool connected as follows:
- Ignition ON,
- Selector lever in position D,
- Winter mode alternately on and off.

Activate SOLENOID 2-3 in ISAT menu READ ON/OFF.

Nominal values are:
- Winter mode ON results in solenoid 2-3 ON,
- Winter mode OFF results in solenoid 2-3 OFF.

If the measurement result is correct, go to step 10.

If the measurement result is wrong, go to step 3.

3. With the ignition switched ON, disconnect connector H10-3 located behind the battery in the engine compartment. (Grey 10-pin Packard connector).

Connect an ohm meter between pin 2 (female) and the battery's negative terminal. Nominal resistance is 10-20 ohms.

If the ohm meter shows the correct value, go to step 7.

If the ohm meter shows a different value, go to step 4.

4. With the ignition switched ON, disconnect connector 531 on the transmission. (Black 8-pin Packard connector).

Connect an ohm meter between pin 3 (male) and the battery's negative terminal. Nominal resistance is 10-15 ohms.

If the ohm meter shows the correct value, go to step 5.

If the ohm meter shows a different value, check the pins in the connector or the wiring to the solenoid valve and remedy any faults. If you cannot find any faults, install a new solenoid valve.





5. With the ignition switched ON, carry out continuity measuring of the wiring between connector H10-3 pin 2 (female) and connector 531 pin 3 (female).
Connect an ohm meter as described above.

Nominal resistance is <1 ohm.

Also check the resistance between connector H10-3 pin 4 (male) and connector 531 pin 3 (male) and 531 pin 5 (male). Nominal resistance is infinite ohms.

If the ohm meter shows the correct value, go to step 6.

If the ohm meter shows a different value, check the connectors and the wiring between them and remedy any faults.

6. Check connector H10-3 for slide-outs and remedy any faults.

Go to step 10.

7. Connect connector XC10 behind the battery.

With the ignition switched off, connect a BOB between the Transmission Control Module (TCM) and the wiring.

Connect an ohm meter between pin 3 and the battery's negative terminal. Nominal resistance is 10 - 20 ohms.

If the ohm meter shows the correct value, go to step 8.

If the ohm meter shows a different value, check the connectors and the wiring between them and remedy any faults.





8. Read the state of the solenoid (on/off) with the ignition switched ON by initiating READ SOLENOID 2-3 in the ISAT scan tool menu with the selector lever in position D and Winter mode alternately activated and not activated. Also check the voltage in pin 1 with a voltmeter.

Nominal values: see table.

Nominal Values Table:

If ISAT and the voltmeter show the correct values, go to step 9.

If ISAT and the voltmeter show different values, go to "Actions Before Changing a TCM".

9. Activate solenoid S2 by initiating SOLENOID 2-3 in ISAT menu ACTIVATE. The solenoid valve is checked with a frequency of 1 Hz, i.e. switching on and off once every second. Listen for a clicking sound in the solenoid.

If the solenoid clicks, go to step 10.

If the solenoid does not click, go to "Actions Before Changing a TCM".

10. Clear the fault code, start and test-drive the car and check if the fault code reappears.

If a fault code is recorded, go to "Actions Before Changing a TCM".