The Idle Speed Control Actuator(ISCA) is installed on the intake manifold and controls the intake airflow that is bypassed around the throttle plate to keep constant engine speed when the throttle valve is closed. The function of the ISCA valve is to maintain idle speed according to various engine loads and conditions, and also to provide additional air during starting. The ISCA valve consists of an opening coil, a closing coil, and a permanent magnet. Based on information from various sensors, the ECM controls both coils by grounding their control circuits. According to the control signals from the ECM, the valve rotor rotates to control the by pass airflow into the engine.
PCM sets DTC P1516 if the PCM detects that the ISCA(Coil 2) signal is incorrect.
Item
Detecting Condition
Possible Cause
DTC Strategy
? Monitor deviation between target idle speed and actual engine speed
? Open or short to ground in harness
? Contact resistance in connectors
? Faulty ISCA valve
Enable Conditions
? Vehicle speed=0
? Coolant temperature >74?(165?)
? Throttle angle: closed
? 20seconds after engine start.
? Engine load <500mg/stroke
? 10V< Battery voltage <16
? No relevant failure
Threshold Value
? Target idle speed-Engine speed > 100rpm (Engine speed too low)
Diagnostic Time
30 seconds
ISCA COIL #1 (OPEN)
Temp.(?)
ISCA Coil #2 (CLOSE)(O)
-20
-4
12.1 ~ 13.7
40
104
15.7 ~ 17.3
-10
14
12.8 ~ 14.4
50
122
16.3 ~ 17.9
0
32
13.4 ~ 15.0
60
140
16.9 ~ 18.5
10
14.0 ~ 15.6
70
158
17.4 ~ 19.0
20
68
14.5 ~ 16.1
80
176
18.0 ~ 19.6
30
86
15.1 ~ 16.7
100
212
19.2 ~ 20.8
ISCA COIL #2 (CLOSE)
ISCA Coil #1 (OPEN)(O)
9.2 ~ 10.8
12.0 ~ 13.6
9.7 ~ 11.3
12.4 ~ 14.0
10.2 ~ 11.8
12.9 ~ 14.5
10.6 ~ 12.2
11.1 ~ 12.7
13.8 ~ 15.4
11.5 ~ 13.1
14.7 ~ 16.3