QOS4 PREHEATING SYSTEM
GENERAL DESCRIPTION
QOS4 preheating system features a quick-on glow plug
with thermometer control of the glowing time and the
afterglow time function.
The system consists of the ECM, indicator lamp, ECT
sensor, vehicle speed sensor, relay and temperature
self-control type glow plugs.
With the employment of the ECT sensor, the glow time
changes according to the engine coolant temperature,
thus allowing optimum starting conditions to be
obtained.
The after glow time function is controlled by ECM.
NOTE:
Refer to DTC P0380 and P0381 in Section 6E.
SYSTEM DIAGRAM
+
-
KEY
50A
ECM
50A
GLOW
50A
2
WHT/
RED
0.5
BLK/
BLU
ECM
J1-15
3
WHT/
RED
3
RED/
BLK
MAIN
80A
8BLK/RED
Glow
Relay
GLOW PLUG 4
BATT
Heater & A/C
Relay
060RW132
1 Inspection on Quick Heating Operation
1. Disconnect ECT-sensor connection on the
thermostat housing
Legend
(1) ECT Sensor
(2) EVRV
2. Connect the circuit tester between glow plug and
engine earth.
3. Inspect the following items with starter switch set to
ON position (but do not start the engine).
1) The glow indicator shall light for about 5 sec.
2) The circuit tester shall indicate power supply
voltage for 9 – 13 sec.
If above specifications are not satisfied, inspect
wire harness, glow relay and ECT-sensor. If
satisfied, inspect glow plug.
2 Inspection on Afterglow Operation
1. Disconnect ECT-sensor connection on the
thermostat housing
Legend
(1) ECT Sensor
(2) EVRV
2. Connect the circuit tester between glow plug and
engine earth.
3. Inspect the following item with the engine started.
1) The circuit tester shall indicate about 7 volts
after 360 seconds of engine start.
• If above specifications are not satisfied, inspect
battery voltage, engine earth, wiring harness,
glow plug, and ECM.
1
2
060RW166
065RW035
1
2
060RW166
065RW035
INSPECTION ON QOS4 SYSTEM OPERATION
ECT SENSOR
Measure the resistance depending on the water
temperature.
Temperature (°C) Current (mA) Resistance (kΩ)
20 ± 1 1.0 2.0 – 3.0
50 ± 1 1.0 0.6 – 1.0
When installing the ECT sensor, apply sealant (Loctite
#262 or equivalent) to prevent water leakage.
Torque: 8 N·m (0.8 kg·m/69 lb in)
Legend
(1) Sealing Material
GLOW PLUG
Inspect the resistance
Resistance at normal temperature: 0.8 – 1.0 Ω
Torque: 23 N·m (2.3 kg·m/17 lb·ft)
GLOW PLUG RELAY
Inspect the continuity
(2) – (4) No Continuity
(1) – (3) Continuity
If battery voltage is applied to the terminal between (1)
– (3)
(2) – (4) Continuity
065RW058
065RW061
1
065RW060
2
42
31
1
3
4
065RW037