COMBUSTION TYPE POWER HEATER SYSTEM, Diagnostic DTC:050,052,054 and 056

DTC Code DTC Name
050 Detection of No Ignition
052 Safety Time Exceeded
054 High Setting of Flame Cutout
056 Low Setting of Flame Cutout

DESCRIPTION

DTC Code

DTC Detection Condition

Trouble Area

050

The ECU is locked as a result of 10 successive heater ignition failures (DTC 052 is detected 10 times in a row).

  • Fuel pipe

  • Air duct

  • No. 1 exhaust pipe sub-assembly

  • No. 2 exhaust pipe sub-assembly

  • Fuel filter assembly

  • Heater pump assembly

  • Heater assembly (ECU)

052

A heater ignition failure is detected.

  • Fuel pipe

  • Air duct

  • No. 1 exhaust pipe sub-assembly

  • No. 2 exhaust pipe sub-assembly

  • Fuel filter assembly

  • Heater pump assembly

  • Heater assembly (ECU)

054

Combustion ends abnormally (high output operation).

  • Fuel pipe

  • Air duct

  • No. 1 exhaust pipe sub-assembly

  • No. 2 exhaust pipe sub-assembly

  • Fuel filter assembly

  • Heater pump assembly

  • Heater assembly (ECU)

056

Combustion ends abnormally (low output operation).

  • Fuel pipe

  • Air duct

  • No. 1 exhaust pipe sub-assembly

  • No. 2 exhaust pipe sub-assembly

  • Fuel filter assembly

  • Heater pump assembly

  • Heater assembly (ECU)

CAUTION / NOTICE / HINT

CAUTION:

  • In some cases, the heater assembly, air duct and exhaust pipes are extremely hot. When performing the inspection, wear protective gloves and do not touch these parts with bare hands.

  • When performing the inspection, wear a face mask to prevent direct inhalation of exhaust gas.

Tip:

  • Output of DTC 050 indicates that the heater assembly has been locked by the ECU and cannot be operated. Clear the DTCs by pressing the memory clear buttons on the DTC tester to unlock the ECU (Click here).

  • Before performing the following inspections, attempt to restart the heater assembly. If the heater assembly is successfully started, confirm that neither DTC 054 nor DTC 056 is output. If neither DTC 054 nor 056 is output, stop troubleshooting because it can be concluded that the system has returned to normal.

PROCEDURE

  1. INSPECT FUEL PIPE

    1. Check that there is no fuel leakage between the heater pump assembly and heater assembly.

      OK

      There is no problem in the fuel pipe.

    CLEAN OR REPLACE FUEL PIPE

    (Click here)

  2. INSPECT AIR DUCT

    1. Perform the following checks of the air duct.

      • The air duct is not clogged with foreign matter.

      • Air intake is normal.

      • The air duct is correctly installed to the heater assembly.

      • There are no defects that would cause air to leak from the intake air duct.

      OK

      There is no problem with the air duct.

    CLEAN OR REPLACE AIR DUCT

    (Click here)

  3. INSPECT EXHAUST PIPE SUB-ASSEMBLY

    1. Check that hot exhaust gas is coming out of the exhaust pipes.

      CAUTION:

      • The exhaust pipes and muffler are extremely hot. Wear protective gloves and do not touch these parts with bare hands.

      • When performing the inspection, wear a face mask to prevent direct inhalation of exhaust gas.

      Table 1. Result

      Result

      Proceed to

      There is no problem with the exhaust pipes.

      A

      There is a problem with the exhaust pipe (No. 1 exhaust pipe sub-assembly).

      B

      There is a problem with the exhaust pipe (No. 2 exhaust pipe sub-assembly).

      C

    CLEAN OR REPLACE NO. 1 EXHAUST PIPE SUB-ASSEMBLY

    (Click here)

    CLEAN OR REPLACE NO. 2 EXHAUST PIPE SUB-ASSEMBLY

    (Click here)

  4. INSPECT HEATER PUMP ASSEMBLY

    1. E176914E07

      Remove the heater pump assembly with the fuel hose still connected (Click here).

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      1 (B2) - 2 (E2)

      Always

      9 to 12 Ω

    3. Apply battery voltage to the heater pump assembly and check the pressure of the hose by hand.

      OK

      Measurement Condition

      Specified Condition

      Battery positive (+) → Terminal 1

      Battery negative (-) → Terminal 2

      Pressure is applied to the hose
      Note:

      • This inspection must be done quickly (within 10 seconds) to prevent damage to the heater pump assembly.

      • Always switch the voltage on and off on the battery side, not the heater pump assembly side.

      • Keep the heater pump assembly as far away from the battery as possible.

    REPLACE HEATER PUMP ASSEMBLY

    (Click here)

  5. REPLACE FUEL FILTER ASSEMBLY

    1. Replace the fuel filter assembly with a new one (Click hereClick here).

    2. Check that the system returns to normal.

      OK

      Heater assembly ignition begins normally and the heater assembly starts operating.

    END (FUEL FILTER ASSEMBLY IS FAULTY)

    REPLACE HEATER ASSEMBLY

    (Click here)