Component Location
General Description
Preheating on Diesel engine improves cold starting with glow plug which heat combustion chamber. Preheating before starting improves cold starting, preheating after starting reduces to generate white smog. GCU(Glow plug Control Unit) is installed on the upper side of timing chain cover and is operated by 12V power supply. GCU receives sensors data such as 1)engine coolant temperature, 2)engine rpm, 3)fuel injection amount from ECM via CAN communication in order to control glow plug. GCU controls 1)glow plug operation with PWM, 2)compensates voltage when low voltage 3)controls not to flow over current on glow plug 4) retrieves DTC after diagnosing each glow plug corresponding to engine condition.
ISS(Instant Starting System) operated by 4.4Valtage, which is slim and enhanced heating performance, is newly adopted on S engine. GCU emerges battery voltage to glow plug directly for 1~ 2sec. at IG key ON. After that, GCU controls glow plug operating voltage with PWM corresponding to Engine condition. ISS glow plug is increased to 1000? within 2 ~3sec. so that starting performance is reached as same level as gasoline. In addition, it is realized that consumption of electricity is optimized by PWM control.
DTC Description
DTC P0671 is set if power supply is not supplied to main power circuit on GCU under IG ON condition. This DTC is retrieved when main power of GCU is short to battery/ground, open or faulty GCU.
DTC Detecting Condition
Item | Detecting Condition | Possible Cause |
DTC Strategy | ? Voltage monitoring | ? GCU main power supply ? Faulty GCU |
Enable Conditions | ? IG key ON |
Threshold Value | GCU main power supply circuit is ? Short to battery. ? Short to ground. ? Open. |
Diagnostic Time | ? 0.6 sec. |
Fail Safe | Fuel cut | NO | |
EGR Off | NO |
Fuel Limit | NO |
Check Lamp | OFF |
Specification
?Preheating time before starting?
Coolant Temp. | Operating Time | Coolant Temp. | Operating Time | Coolant Temp. | Operating Time | Coolant Temp. | Operating Time | Coolant Temp. | Operating Time |
- 25 ? | 21 sec. | - 20 ? | 18 sec. | - 10 ? | 8 sec. | 5 ? | 2 sec. | 15 ? | 1.5 sec. |
?Preheating time at starting?Over 45 RPM , Maximum for 30sec under -80 ? condition.
?Preheating time after starting?
Coolant Temp. | Operating Time | Coolant Temp. | Operating Time | Coolant Temp. | Operating Time | Coolant Temp. | Operating Time | Coolant Temp. | Operating Time |
- 25 ? | 300 sec. | - 20 ? | 300 sec. | - 10 ? | 300 sec. | 60 ? | 300 sec. | 90 ? | 0 sec. |
Diagnostic Circuit
Signal Waveform