P1546

Article Updated by TSB-05-13-013

DTC P1546: DOR Radiator Tampering Monitor (Temperature Check at Cold Start)

Radiator Sensor Circuit Part 1:

Radiator Sensor Circuit Part 2:

CIRCUIT OPERATION
- The battery voltage is applied from the ignition switch to the radiator sensor (terminal No.3), and it is grounded to the vehicle body from the radiator sensor (terminal No.1).
- The radiator sensor (terminal No.2) sends the sensor signal to the powertrain control module (terminal No.3).

MONITOR EXECUTION
- Once per driving cycle

MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable

Sensor (The sensor below is determined to be normal)
- Not applicable

DTC SET CONDITIONS

Logic Flow Chart:

Logic Flow Chart

Check Condition
- Battery positive voltage is higher than 11 volts.
- Intake air temp from 0 degrees C (32 degrees F) to 40 degrees C (104 degrees F).
- Engine coolant temperature is less than 40 degrees C (104 degrees F) at engine start.
- The engine coolant temperature - intake air temperature is 5 degrees C (41 degrees F) or less at engine start.

Judgement Criteria
- When the difference between the radiator sensor output temperature after the engine is started and the coolant temperature is 15 degrees C (59 degrees F) or more.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 19. OBD-II Drive Cycle Pattern Lists

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)
- Tampering of the DOR radiator

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A

STEP 1. DOR radiator sensor installation check

- Check that the sensor is installed securely and operates normally.

Q: Is the check result normal?

YES: Go to Step 2.
NO: Replace the DOR radiator. Then go to Step 3.

STEP 2. Replace the DOR radiator

1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 19. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).

Q: Is DTC P1546 set?

YES: Replace the PCM. Then go to Step 3.

NO: The procedure is complete.

STEP 3. Perform the OBD-II drive cycle.

1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle Pattern 19. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).

Q: Is DTC P1546 set?

YES: Repeat the troubleshooting.

NO: The procedure is complete.