P1999 Air Heater Malfunction Hyundai D6CA
GENERAL INFORMATION
COMPONENT LOCATION
DESCRIPTION
1. GENERAL DESCRIPTION
The air heater heats air entering into combustion chamber when the engine is cold to make diesel spread and ignite well and functions to reduce soot from exhaust gas when the engine is cold. ETCM controls the drive and drive time of engine pre-heat auxiliary relay to supply power to air heater based on such information as the engine coolant temperature and the ignition key on. And the ETCM displays power supply status of air heater through gage lamp to a driver.
Generally the air heater lamp comes off when the ignition turns ON but comes on as much as preheat time according to engine temperature.
Using air heater lamp test among actuator tests of scan tool, the operation condition of the air heater lamp can be checked in brief. If the air heater lamp comes on while driving, troubleshooting in preheat circuit and relay system should be performed.
2. DTC DESCRIPTION
The DTC is set when the drive voltage of air heater entering into ETCM differs from air heater control condition of ETCM. The probable causes are air heater drive circuit and relay. In this case ETCM warns a driver by blinking a pre-heat lamp. It is possible to drive but the proper action should be taken through a prompt check.
DTC DETECTING CONDITION
| Item | Detecting Condition | Possible Cause | ||
| DTC Strategy | • Voltage monitoring | • Short to ETCM output ground |
||
| Enable Conditions |
• Ignition ON | |||
| Threshold Value |
• Air heater opposite operation according to operation condition | |||
| Diagnosis Time |
• Above 60 seconds | |||
| Fail Safe | Fuel Cut | No | • Possible normal drive • Pre-heat lamp ON (Initial starting problem, over-white smoke) • Air heater operation stop(Pre- heat overheating) |
|
| Fuel Limit | No | |||
| MIL | OFF | |||
SPECIFICATION
| 3-5 (20℃ ) | 3-5 when applying power | 3-5 when cutting off power |
| 240Ω±10% | Continuity :1-2 | Infinite: 1-2 |
| Temperature | Above 0℃ | 0°C | -3℃ ~-6℃ | -26℃ ~-28℃ | Pre-heat time |
| Pre-heat (sec.) | 0 | 10 | 30 | 60 | 28 |
Schematic Diagram
W/Harness Inspection
TERMINAL & CONNECTOR INSPECTION
1.Many malfunctions in the electrical system are caused by poor harness, and terminals.
2. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3.Has a problem been found?
Yes
▶ Repair as necessary and then go to “Verification of Vehicle Repair” procedure.
No
▶ Go to “Signal Circuit Inspection” procedure.
SIGNAL CIRCUIT INSPECTION
1.Air Heater Sub-relay Power Supply Voltage Inspection
(1)Disconnect the air heater sub-relay(M97).
(2) Turn the ignition ON. Leave the engine OFF.
(3)Measure the voltage of terminals 1 and 5 of air heater sub-relay harness side connector.
■ Specification: Battery power(B+ V)
(4) Is the voltage measured within specification?
Yes
▶ Go to “Control Circuit Inspection” procedure.
No
▶ Go to “Air Heater Sub-relay Power Supply Open Inspection” procedure.
2.Air Heater Sub-relay Power Supply Open Inspection
(1) Turn the ignition OFF.
(2)Disconnect the air heater sub-relay(M97) and the ETCM connector(E20, C40).
(3)Disconnect the fuse #32(5A) and measure resistance between terminal of fuse #32 and terminal 5 of the air heater sub-relay harness side connector.
(4)Disconnect the fuse #47(10A) and measure resistance between terminal of fuse #47 and terminal 1 of the air heater sub-relay harness side connector.
■ Specification: Continuity(Below 1.0 Ω)
(5) Is the resistance measured within specification?
Yes
▶ Go to “Signal Short to Power Inspection” procedure.
No
▶ Repair open in circuit and then go to “Verification of Vehicle Repair” procedure.
3.Signal Short to Power Inspection
(1)Disconnect fuse #32(5A), fuse #47(10A), air heater sub-relay(M97) and ETCM connector(E20,C40).
(2) Turn the ignition ON. Leave the engine OFF.
(3)Measure voltage between terminal 2 of air heater sub-relay harness side connector and chassis ground.
■ Specification: Below 0~0.1V
(4) Is the voltage measured within specification?
Yes
▶ Go to “Control Circuit Inspection” procedure.
No
▶ Repair short to power and then go to “Verification of Vehicle Repair” procedure.
CONTROL CIRCUIT INSPECTION
1.Air Heater Sub-relay Control Voltage Inspection
(1)Disconnect the air heater sub-relay(M97).
(2) Turn the ignition ON. Leave the engine OFF.
(3)Measure the voltage of terminal 3 of the air heater sub-relay harness side connector.
■ Specification: ETCM output power approx. 4V
(4) Is the voltage measured within specification?
Yes
▶ Go to “Component Inspection” procedure.
No
▶ Go to “Control Open Inspection” procedure.
2.Control Open Inspection
(1) Turn the ignition OFF.
(2)Disconnect air heater sub-relay(M97), ETCM connector(E20, C40).
(3)Measure resistance between terminal 3 of air heater sub-relay and terminal 50 of ETCM connector (C40).
■ Specification: Continuity(Below 1.0 ohm)
(4) Is the resistance measured within specification?
Yes
▶ Go to “Control Short to Power Inspection” procedure.
No
▶ Repair open in circuit and then go to “Verification of Vehicle Repair” procedure.
3.Control Short to Power Inspection
(1)Disconnect fuse #32(5A), fuse #47(10A), air heater sub-relay(M97) and ETCM connector(E20,C40).
(2) Turn the ignition ON. Leave the engine OFF.
(3)Measure voltage between terminal 3 of air heater sub-relay harness side connector and chassis ground.
(4)Measure voltage between terminal 50 of ETCM(C40) and chassis ground.
■ Specification: Below 0~0.1V
(5) Is the voltage measured within specification?
Yes
▶ Go to “Component Inspection” procedure.
No
▶ Repair short to power and then go to “Verification of Vehicle Repair” procedure.
COMPONENT INSPECTION
1.Air Heater Sub-relay Component Resistance Inspection
(1) Turn the ignition OFF.
(2)Remove the air heater relay(M97).
(3)Measure the coil resistance between terminal 3 and 5 of air heater sub-relay.
■ Specification: 240Ω±10%(20℃)
(4) Is the coil resistance of air heater sub-relay normal?
Yes
▶ Go to “Air Heater Sub-relay Component Operation Inspection” procedure.
No
▶ Replace the air heater sub-relay and then go to “Verification of Vehicle Repair” procedure.
2.Air Heater Sub-relay Component Operation Inspection
(1) Turn the ignition OFF.
(2)Disconnect the air heater sub-relay(M97).
(3) Apply battery power to terminal 5 of air heater sub-relay, provide ground to terminal 3 of air heater sub-relay
(4)Measure resistance between terminal 1 and 2 of the air heater sub-relay.
■ Specification:
When Cut-off power: Infinite
When applying power: Continuity
(5) Is the resistance of air heater sub-relay normal according to power condition?
▶ Go to “Air Heater Component and Fuse Inspection” procedure.
▶ Replace the air heater sub-relay and then go to “Verification of Vehicle Repair” procedure.
Repeat above inspection 2 or 3 times.
3.Air Heater Component and Fuse Inspection
(1) Turn the ignition ON. Leave the engine OFF.
(2)Check the air heater for broken heater element, poor connection and wide clearance etc.
(3)Replace with new fuses as necessary after checking the fuse condition of air heater and getting rid of the probable causes.
(4) Are the air heater component and the fuse normal?
Yes
▶ Go to “Verification of Vehicle Repair” procedure.
No
▶ Replace the air heater component and defective fuses and then go to “Verification of Vehicle Repair” procedure.
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1.Connect scan tool and select “Diagnostic Trouble Codes(DTCs)” mode and then clear DTC.
2.Drive the vehicle under conditions noted in failure records.
3.Did the DTC return?
Yes
▶ Go to the applicable DTC procedure.
No
▶ System OK.
