DTC P0890 TCM Power Relay Sense Circuit Low: Notes

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Gear is not changed.

CAUTION:

After diagnosis, perform Clear Memory Mode for ECM. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Clear Memory Mode . Ref. to ENGINE (DIAGNOSTICS) (H4DO)>Clear Memory Mode .
Use CHECK BOARD when measuring the TCM terminal voltage and resistance.

Wiring diagram:

CVT control system Ref. to WIRING SYSTEM>CVT Control System .

Fig 1: TCM Power Relay Sense Circuit Low System Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

CHECK HARNESS.
1. Disconnect the TCM connector.
2. Remove the self shut relay.
3. Measure the resistance between TCM connector and relay holder.
  Connector & terminal
  
  (B54) No. 25 - (B220) No. 16:
  
  (B54) No. 8 - (B220) No. 15:
  
  (B54) No. 24 - (B220) No. 15:
  
  (B54) No. 40 - (B220) No. 15:
Is the resistance less than 1 Ω?
- Yes : Go to 2.
- No : Repair the open circuit of harness.
CHECK HARNESS.
Measure the resistance between TCM connector and chassis ground.

Connector & terminal

(B54) No. 25 - Chassis ground:

(B54) No. 8 - Chassis ground:

(B54) No. 24 - Chassis ground:

(B54) No. 40 - Chassis ground:

Is the resistance 1 MΩ or more?
- Yes : Go to 3.
- No : Repair the short circuit of harness.
CHECK RELAY POWER SUPPLY.
Measure the voltage between relay holder and chassis ground.

Connector & terminal

(B220) No. 14 (+) - Chassis ground (-):

(B220) No. 17 (+) - Chassis ground (-):

Is the voltage 10 V or more?
- Yes : Go to 4.
- No : Repair the open or short circuit of harness.
CHECK SELF SHUT RELAY.
Measure the resistance between self shut relay terminals.

Terminals

No. 16 - No. 17:

Is the resistance 110 - 140 Ω?
- Yes : Go to 5.
- No : Replace the self shut relay.
CHECK SELF SHUT RELAY.
Measure the resistance between self shut relay terminals.

Terminals

No. 14 - No. 15:

Is the resistance 1 MΩ or more?
- Yes : Go to 6.
- No : Replace the self shut relay.
CHECK INPUT SIGNAL FOR TCM.
1. Connect the TCM connector.
2. Install the self shut relay.
3. Read the data of [Control Module Voltage] using Subaru Select Monitor.
Is [Control Module Voltage] 10 V or more?
- Yes : Current condition is normal. Check for poor contact in connectors or harnesses, and repair the defective part.
- No : Go to 7.
CHECK SELF SHUT RELAY.
1. Turn the ignition switch to OFF.
2. Replace the self shut relay.
3. Clear the memory. Ref. to TRANSMISSION (DIAGNOSTICS)>Clear memory .
4. Read the DTC.
Is DTC P0890 displayed?
- Yes : Replace the TCM. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR580)>Transmission Control Module (TCM) . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR690)>Transmission Control Module (TCM) .
- No : The original self shut relay is defective.