1A
Idle Air Control System Check
Wiring Diagram
1. IAC valve 4. “IG” fuse 7. “FI” fuse
2. ECM 5. Ignition switch 8. “IGN1” fuse
3. Main relay 6. Relay box 9. A/C signal, PNP signal and headlight signal
Troubleshooting
Step Action YES NO
1
1) Check engine idle speed and IAC duty referring to Idle Speed / Idle Air Control (IAC) Duty Inspection:M13A without VVT .
Is idle speed within specification?
Go to Step 2.
Go to Step 4.
2
Is IAC duty within specification in Step 1?
Go to Step 3.
Check for the followings: Vacuum leak, EVAP canister purge control system, Clog of IAC air passage, Accessory engine load. Closed throttle position (TP sensor), Stuck of PCV valve.
3
Is engine idle speed kept specified speed even with headlight ON?
System is in good condition.
Go to Step 8.
4
Was idle speed higher than specification in Step 1?
Go to Step 5.
Go to Step 6.
5
1) Check A/C (input) signal circuit referring to Step 2 of A/C Signal Circuits Check (Vehicle with A/C):M13A without VVT , if equipped. (A/C signal can be also checked by using SUZUKI scan tool.)
Is it in good condition?
Go to Step 6.
Repair or replace A/C signal circuit or A/C system.
6
Is vehicle equipped with A/T?
Go to Step 7.
Go to Step 10.
7
Do you have SUZUKI scan tool?
Go to Step 8.
Go to Step 9.
8
Check PNP signal (“D” range signal)
1) Connect SUZUKI scan tool to DLC with ignition switch OFF.
2) Turn ignition switch ON and display when shifting selector lever to each range.
Is check result satisfactory?
Go to Step 10.
Repair or replace.
9
Check PNP signal (“D” range signal)
1) Turn ignition switch ON.
2) Check voltage at terminal “E113-6” of ECM connector connected.
Is check result satisfactory?
Go to Step 10.
Repair or replace.
10
Do you have SUZUKI scan tool?
Go to Step 11.
Go to Step 12.
11
Check Idle Air Control System
1) Connect SUZUKI scan tool to DLC with ignition switch OFF, set parking brake and block drive wheels.
2) Warm up engine to normal operating temperature.
3) Clear DTC and select “MISC TEST” mode on SUZUKI scan tool.
Is check result satisfactory?
Go to Step 13.
Go to Step 14.
12
Check Idle Air Control System
1) Remove IAC valve from throttle body referring to Idle Air Control (IAC) Valve Removal and Installation:M13A .
2) Check IAC valve for operation referring to Idle Air Control (IAC) Valve On-Vehicle Inspection:M13A .
Is check result satisfactory?
Go to Step 13.
Go to Step 14.
13
Was IAC duty less than about 3% (or more than about 97% for OFF duty meter) in Step 1 of this table?
Check abnormal air inhaling from air intake system, PCV valve and EVAP canister purge control system.
Check TP sensor (Closed throttle position) and ECT sensor for performance. If sensors are oK, substitute a known-good ECM.
14
Check wire harness
1) Disconnect IAC valve connector.
2) Turn ignition switch ON, check voltage between “BLU/BLK” wire terminal of IAC valve connector and vehicle body ground.
Is voltage 10 – 14 V?
Go to Step 11.
“BLU/BLK” wire circuit open.
15
Check wire harness
1) Disconnect ECM connectors with ignition switch OFF.
2) Measure resistance between “GRN/YEL” wire terminal of IAC valve connector and vehicle body ground.
Is resistance infinity?
Go to Step 16.
“GRN/YEL” wire circuit shorted to ground.
16
Check wire harness
1) Turn ignition ON.
2) Measure voltage between “GRN/YEL” wire terminal of IAC valve connector and vehicle body ground.
Is voltage about 0 V?
Go to Step 17.
“GRN/YEL” wire circuit shorted to power.
17
Check wire harness
1) Turn ignition switch OFF.
2) Measure resistance between “E115-6” terminal of ECM connector and “GRN/YEL” wire terminal of IAC valve connector.
Is resistance below 3 Ω?
Go to Step 18.
“GRN/YEL” wire circuit open.
18
Check wire harness
1) Measure resistance between “BLK” wire terminal of IAC valve connector and vehicle body ground.
Is resistance continuity?
Go to Step 19.
“BLK” wire circuit open.
19
Check IAC valve signal
1) Connect IAC valve and ECM connectors.
2) Using oscilloscope, check that IAC valve duty pulse is outputted referring to “Reference waveform No.18” in Inspection of ECM and Its Circuits:M13A without VVT and “Reference waveform No.19” in Inspection of ECM and Its Circuits:M13A without VVT .
Is duty pulse outputted at “E115-6” of ECM terminal?
Replace IAC valve.
Go to Step 20.
20
Check wire harness
1) Disconnect ECM connectors with ignition switch OFF.
2) Using service wire, ground “E114-10” terminal of ECM connector because of main relay turned ON.
3) Turn ignition switch ON, measure voltage between “E115-6” terminal of ECM connector and vehicle body ground.
Is voltage 10 – 14 V?
Substitute a known-good ECM and recheck.
Replace IAC valve.