P1546

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

Radiator Sensor Circuit Part 1:

Radiator Sensor Circuit Part 2:

RADIATOR SENSOR CIRCUIT

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 °C (32 °F) to 40 °C (104 °F).
- Engine coolant temperature is less than 40 °C(104 °F) at engine start.
- The engine coolant temperature - intake air temperature is 5 °C (41 °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 °C (59 °F) or more.

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

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
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
2. Check the diagnostic trouble code (DTC).

Q: Is DTC P1546 set?

YES: Repeat the troubleshooting.

NO: The procedure is complete.