NO.10 LOW IDLE/STALLS DURING DECELERATION [MZR-CD (RF Turbo)]


10	LOW IDLE/STALLS DURING DECELERATION
DESCRIPTION	• Engine stops unexpectedly at beginning of deceleration or recovery from deceleration.
POSSIBLE CAUSE	• Intake-air system restriction • Poor fuel quality • A/C system improper operation • Inadequate fuel pressure • Suction control valve malfunction (built-in supply pump) • Fuel pressure limiter malfunction (built-in common rail) • Fuel leakage • Fuel line restriction • Fuel filter clogging • Incorrect fuel injection timing • Improper idle speed • Erratic signal from CKP sensor • Erratic signal from CMP sensor • Supply pump malfunction • Fuel injector malfunction • Low engine compression • Improper valve timing • Glow system malfunction • EGR system malfunction • Vacuum leakage • MAF/IAT sensor or related circuit malfunction • ECT sensor or related circuit malfunction • Fuel pressure sensor or related circuit malfunction • Neutral switch malfunction or related circuit malfunction • CPP switch malfunction or related circuit malfunction • Accelerator pedal position sensor or related circuit malfunction • Idle switch or related circuit malfunction • Incorrect adjustment accelerator pedal position sensor and/or idle switch • IDM or related circuit malfunction Warning The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: • Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. • Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR-CD (RF Turbo)].) (See AFTER SERVICE PRECAUTION [MZR-CD (RF Turbo)].)


STEP	INSPECTION	RESULTS	ACTION
1	Does the engine idle rough?	Yes	Go to symptom troubleshooting "NO.8 ENGINE RUNS ROUGH/ROLLING IDLE". (See NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [MZR-CD (RF Turbo)].)
1	Does the engine idle rough?	No	Go to the next step.
2	Inspect for the following: • Fuel line/fuel filter clogging • Intake-air system restriction • Vacuum leakage • Fuel quality (e.g.: include water contamination, winter/summer blend) Are all items normal?	Yes	Go to the next step.
2		No	Service if necessary. Repeat Step 2.
3	Perform self-test function using the WDS or equivalent. Turn the engine switch to the ON position. Retrieve any DTC. Is DTC displayed?	Yes	DTC is displayed: Go to the applicable DTC inspection. (See DTC TABLE [MZR-CD (RF Turbo)].) Communication error message is displayed: Inspect for the following: • Open circuit between PCM control relay and PCM terminal 53 or 79 • Open circuit PCM control relay and PCM terminal 69 • PCM control relay stuck open • Open or poor GND circuit (PCM terminal 65, 85, 103 or 104) • Poor connection vehicle body GND
3		No	No DTC is displayed: Go to the next step.
4	Inspect idle speed. (See IDLE SPEED INSPECTION [MZR-CD (RF Turbo)].) Is idle speed correct?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning part according to the idle speed inspection results.
5	Inspect the adjustment of the accelerator pedal position sensor and the idle switch. Are the accelerator pedal position sensor and the idle switch adjusted correctly?	Yes	Go to the next step
5		No	Adjust the accelerator pedal position sensor and the idle switch correctly.
6	Measure the voltage at PCM terminal 33 and 56. Is the voltages normal?	Yes	Go to the next step.
6		No	PCM terminal 33 does not specified: Inspect the clutch pedal position switch and the related wiring harness. PCM terminal 56 does not specified: Inspect the neutral switch and the related wiring harness.
7	Visually inspect the CKP sensor and teeth of the pulse wheel. Are the CKP sensor and teeth of the pulse wheel normal?	Yes	Go to the next step.
7		No	Replace the malfunctioning parts.
8	Measure the gap between the CKP sensor and teeth of the pulse wheel. Specification 1.5-2.5 mm {0.059-0.098 in} Is the gap within the specification?	Yes	Go to the next step.
8		No	Adjust the CKP sensor position.
9	Visually inspect the CMP sensor and teeth of the pulse wheel. Are the CMP sensor and teeth of the pulse wheel normal?	Yes	Inspect the following PIDs: (See PCM INSPECTION [MZR-CD (RF Turbo)].) • ECT • IAT • MAF • RPM If PID value is not as specified, repair or replace the malfunctioning part. If PID value is normal, go to the next step.
9		No	Replace malfunctioning parts.
10	Inspect the fuel pressure sensor. (See FUEL PRESSURE SENSOR INSPECTION [MZR-CD (RF Turbo)].) Is fuel pressure normal?	Yes	Go to the next step.
10		No	Replace the common rail.
11	Inspect the suction control valve. (See SUCTION CONTROL VALVE INSPECTION [MZR-CD (RF Turbo)].) Is the suction control valve normal?	Yes	Go to the next step.
11		No	Repair the supply pump. (See SUPPLY PUMP INSPECTION [MZR-CD (RF Turbo)].)
12	Is the engine compression correct? (See COMPRESSION INSPECTION [MZR-CD (RF Turbo)].)	Yes	Go to the next step.
12		No	Inspect for the following: • Damaged valve seat • Worn valve stem and valve guide • Worn or stuck piston ring • Worn piston, piston ring or cylinder • Improper valve timing Service if necessary.
13	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZR-CD (RF Turbo)].) Is the fuel injector normal?	Yes	Go to the next step.
13		No	Repair or replace if necessary.
14	Note • The following test should be performed on the vehicles with the A/C system. If the following test cannot be performed due to the engine stalling, go to the next step. • Go to the next step for the vehicle without the A/C system. Connect a pressure gauge to A/C line. Turn the blower and A/C switches on. Is pressure within the specification?	Yes	Go to the next step.
14		No	A/C is always on: Go to symptom troubleshooting "NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR-CD (RF Turbo)].) Other symptoms: Inspect the following: • Refrigerant charging amount • Cooling fan and/or condenser fan operation
15	Inspect the EGR system operation. Is the EGR system operation normal?	Yes	Go to the next step.
15		No	Repair or replace the malfunctioning part according to the EGR system operation results.
16	Inspect the glow system operation. (See RELAY INSPECTION.) Is the glow system operation normal?	Yes	Remove and inspect the supply pump and the common rail.
16		No	Service if necessary.
17	Verify test results. • If normal, return to diagnostic index to service any additional symptoms. • If malfunction remains, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR-CD (RF Turbo)].)