DTC P2177:00 [L8, LF, L5]

DTC P2177:00	Fuel system too lean at off idle
DETECTION CONDITION	• PCM monitors short term fuel trim (SHRTFT), long term fuel trim (LONGFT) during closed loop fuel control at off-idle. If the LONGFT and the sum total of these fuel trims exceed preprogrammed criteria, the PCM determines that fuel system is too lean at off-idle. Diagnostic support note • This is a continuous monitor. (Fuel system) • MIL illuminates if PCM detects the above malfunctioning condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. • PENDING CODE is available if PCM detects the above malfunction conditions during first drive cycle. • FREEZE FRAME DATA is available. • The DTC is stored in the PCM memory.
POSSIBLE CAUSE	• Misfire • A/F sensor deterioration • A/F sensor heater malfunction • MAF sensor malfunction • Pressure regulator (built-in fuel injection pump) malfunction • Fuel pump malfunction • Fuel filter clogged or restricted • Fuel leakage on fuel line from fuel distributor and fuel pump • Leakage exhaust system • Purge solenoid valve improper operation • Purge solenoid valve malfunction (stuck open) • Purge solenoid hoses improper connection • Air suction in intake air system • Insufficient engine compression • Variable valve timing control system improper operation (LF, L5) • PCM malfunction

DTC P2177:00

Fuel system too lean at off idle

DETECTION CONDITION

• PCM monitors short term fuel trim (SHRTFT), long term fuel trim (LONGFT) during closed loop fuel control at off-idle. If the LONGFT and the sum total of these fuel trims exceed preprogrammed criteria, the PCM determines that fuel system is too lean at off-idle.

Diagnostic support note

• This is a continuous monitor. (Fuel system)

• MIL illuminates if PCM detects the above malfunctioning condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.

• PENDING CODE is available if PCM detects the above malfunction conditions during first drive cycle.

• FREEZE FRAME DATA is available.

• The DTC is stored in the PCM memory.

POSSIBLE CAUSE

• Misfire

• A/F sensor deterioration

• A/F sensor heater malfunction

• MAF sensor malfunction

• Pressure regulator (built-in fuel injection pump) malfunction

• Fuel pump malfunction

• Fuel filter clogged or restricted

• Fuel leakage on fuel line from fuel distributor and fuel pump

• Leakage exhaust system

• Purge solenoid valve improper operation

• Purge solenoid valve malfunction (stuck open)

• Purge solenoid hoses improper connection

• Air suction in intake air system

• Insufficient engine compression

• Variable valve timing control system improper operation (LF, L5)

• PCM malfunction

STEP	INSPECTION	ACTION
1	VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
No	Record the FREEZE FRAME on the repair order, then go to the next step.
2	VERIFY RELATED SERVICE INFORMATION AVAILABILITY • Verify related Service Information availability. • Is any related Service Information available?	Yes	Perform repair or diagnosis according to the available Service information. If the vehicle is not repaired, go to the next step.
No	Go to the next step.
3	VERIFY RELATED PENDING CODE OR STORED DTCS • Switch the ignition to off, then to the ON (Engine off). • Verify related pending code or stored DTCs. • Are other DTCs present?	Yes	If misfire DTC is present, go to Step 8. If other DTC is present, go to the applicable DTC inspection. (See DTC TABLE [L8, LF, L5].)
No	If driveability concern is present, go to Step 8. If not, go to the next step.
4	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA • Is the DTC P2177:00 on FREEZE FRAME DATA?	Yes	Go to the next step.
No	Go to troubleshooting procedures for DTC on FREEZE FRAME DATA.
5	VERIFY CURRENT INPUT SIGNAL STATUS (SWITCH THE IGNITION TO ON/ IDLE) • Access APP1, APP2, ECT, MAF, TP_REL and VSS PIDs using the M-MDS. • Is there any signal that is far out of specification when switch the ignition to ON and the engine runs?	Yes	Inspect the sensor and excessive resistance in related wiring harnesses. Repair if necessary. Then go to Step 17.
No	Go to the next step.
6	VERIFY CURRENT INPUT SIGNAL STATUS UNDER TROUBLE CONDITION • Inspect the same PIDs as Step 5 while simulating FREEZE FRAME DATA condition. • Is there any signal which causes drastic changes?	Yes	Inspect the sensor and related wiring harnesses repair or replace it. Then go to Step 17.
No	Go to the next step.
7	INSPECT A/F SENSOR • Inspect the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR, HEATED OXYGEN SENSOR (HO2S) INSPECTION [L8, LF, L5].) • Is A/F sensor normal?	Yes	Go to the next step.
No	Visually inspect for any gas leakage between the exhaust manifold and the A/F sensor. If normal, replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR, HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [L8, LF, L5].) If the gas leakage is detected, repair or replace malfunctioning part. Then go to Step 17.
8	VERIFY CURRENT INPUT SIGNAL STATUS OF MAF SENSOR • Connect the M-MDS to the DLC-2. • Start the engine. • Access the MAF PID. • Verify that the MAF PID changes quickly according to engine speed. • Is the PID normal?	Yes	Go to the next step.
No	Replace the MAF/IAT sensor, then go to Step 17.
9	INSPECT FOR EXCESSIVE AIR SUCTION OF INTAKE AIR SYSTEM • Visually inspect for looseness, cracks or damage hoses on intake air system. • Is there any malfunction?	Yes	Repair or replace source of air suction, then go to Step 17.
No	Go to the next step.
10	INSPECT PURGE CONTROL SYSTEM OPERATION • Perform the Purge Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF, L5].) • Does the purge control system work properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to inspection result, then go to Step 17.
11	INSPECT FUEL LINE PRESSURE • Switch the ignition to off. • Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [L8, LF, L5].) • Is the fuel line pressure normal?	Yes	Go to Step 13.
No	If the fuel pressure is too high, replace the fuel pump unit, then go to Step 17. If the fuel line pressure is low, go to the next step.
12	INSPECT FUEL LINE FROM FUEL PUMP TO FUEL INJECTOR • Visually inspect fuel line for any leakage. • Is fuel leakage found?	Yes	Replace suspected fuel line, then go to Step 17.
No	Inspect for foreign materials or stain inside fuel filter (low-pressure). If for foreign materials or stain inside fuel filter (low-pressure), clean of fuel tank and filter. Then go to Step 17.
13	INSPECT IGNITION SYSTEM • Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF, L5].) • Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to spark test result, then go to Step 17.
14	INSPECT ENGINE COMPRESSION • Inspect the engine compression. (See COMPRESSION INSPECTION [L8, LF, L5].) • Is it normal?	Yes	Go to the next step. (LF, L5)/Go to Step16. (L8)
No	Implement the engine overhaul for repairs, then go to Step 17.
15	INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION • Inspect variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF, L5].) • Does variable valve timing control system work properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to inspection results, then go to Step 17.
16	INSPECT FUEL INJECTOR OPERATION • Remove the fuel injector. • Inspect the fuel injector (resistance, injection amount). (See FUEL INJECTOR INSPECTION [L8, LF, L5].) • Is the fuel injector normal?	Yes	Go to the next step.
No	Replace the fuel injector, then go to the next step. (See FUEL INJECTOR REMOVAL/INSTALLATION [L8, LF, L5].)
17	VERIFY TROUBLESHOOTING OF DTC P2177:00 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the M-MDS. • Perform the KOER self-test. (See KOEO/KOER SELF TEST [L8, LF, L5].) • Is the DTC P2177:00 present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L8, LF, L5].)
No	Go to the next step.
18	VERIFY AFTER REPAIR PROCEDURE • Perform the “AFTER REPAIR PROCEDURE”. (See AFTER REPAIR PROCEDURE [L8, LF, L5].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [L8, LF, L5].)
No	Troubleshooting completed.

STEP

INSPECTION

ACTION

VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAS BEEN RECORDED

• Has FREEZE FRAME DATA been recorded?

Yes

Go to the next step.

Record the FREEZE FRAME on the repair order, then go to the next step.

VERIFY RELATED SERVICE INFORMATION AVAILABILITY

• Verify related Service Information availability.

• Is any related Service Information available?

Yes

Perform repair or diagnosis according to the available Service information.

If the vehicle is not repaired, go to the next step.

Go to the next step.

VERIFY RELATED PENDING CODE OR STORED DTCS

• Switch the ignition to off, then to the ON (Engine off).

• Verify related pending code or stored DTCs.

• Are other DTCs present?

Yes

If misfire DTC is present, go to Step 8.

If other DTC is present, go to the applicable DTC inspection.

(See DTC TABLE [L8, LF, L5].)

If driveability concern is present, go to Step 8.

If not, go to the next step.

IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA

• Is the DTC P2177:00 on FREEZE FRAME DATA?

Yes

Go to the next step.

Go to troubleshooting procedures for DTC on FREEZE FRAME DATA.

VERIFY CURRENT INPUT SIGNAL STATUS (SWITCH THE IGNITION TO ON/ IDLE)

• Access APP1, APP2, ECT, MAF, TP_REL and VSS PIDs using the M-MDS.

• Is there any signal that is far out of specification when switch the ignition to ON and the engine runs?

Yes

Inspect the sensor and excessive resistance in related wiring harnesses.

Repair if necessary.

Then go to Step 17.

Go to the next step.

VERIFY CURRENT INPUT SIGNAL STATUS UNDER TROUBLE CONDITION

• Inspect the same PIDs as Step 5 while simulating FREEZE FRAME DATA condition.

• Is there any signal which causes drastic changes?

Yes

Inspect the sensor and related wiring harnesses repair or replace it.

Then go to Step 17.

Go to the next step.

INSPECT A/F SENSOR

• Inspect the A/F sensor.

(See AIR FUEL RATIO (A/F) SENSOR, HEATED OXYGEN SENSOR (HO2S) INSPECTION [L8, LF, L5].)

• Is A/F sensor normal?

Yes

Go to the next step.

Visually inspect for any gas leakage between the exhaust manifold and the A/F sensor.

If normal, replace the A/F sensor.

(See AIR FUEL RATIO (A/F) SENSOR, HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [L8, LF, L5].)

If the gas leakage is detected, repair or replace malfunctioning part.

Then go to Step 17.

VERIFY CURRENT INPUT SIGNAL STATUS OF MAF SENSOR

• Connect the M-MDS to the DLC-2.

• Start the engine.

• Access the MAF PID.

• Verify that the MAF PID changes quickly according to engine speed.

• Is the PID normal?

Yes

Go to the next step.

Replace the MAF/IAT sensor, then go to Step 17.

INSPECT FOR EXCESSIVE AIR SUCTION OF INTAKE AIR SYSTEM

• Visually inspect for looseness, cracks or damage hoses on intake air system.

• Is there any malfunction?

Yes

Repair or replace source of air suction, then go to Step 17.

Go to the next step.

INSPECT PURGE CONTROL SYSTEM OPERATION

• Perform the Purge Control System Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF, L5].)

• Does the purge control system work properly?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to inspection result, then go to Step 17.

INSPECT FUEL LINE PRESSURE

• Switch the ignition to off.

• Inspect the fuel line pressure.

(See FUEL LINE PRESSURE INSPECTION [L8, LF, L5].)

• Is the fuel line pressure normal?

Yes

Go to Step 13.

If the fuel pressure is too high, replace the fuel pump unit, then go to Step 17.

If the fuel line pressure is low, go to the next step.

INSPECT FUEL LINE FROM FUEL PUMP TO FUEL INJECTOR

• Visually inspect fuel line for any leakage.

• Is fuel leakage found?

Yes

Replace suspected fuel line, then go to Step 17.

Inspect for foreign materials or stain inside fuel filter (low-pressure).

If for foreign materials or stain inside fuel filter (low-pressure), clean of fuel tank and filter.

Then go to Step 17.

INSPECT IGNITION SYSTEM

• Perform the spark test.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF, L5].)

• Is strong blue spark visible at each cylinder?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to spark test result, then go to Step 17.

INSPECT ENGINE COMPRESSION

• Inspect the engine compression.

(See COMPRESSION INSPECTION [L8, LF, L5].)

• Is it normal?

Yes

Go to the next step. (LF, L5)/Go to Step16. (L8)

Implement the engine overhaul for repairs, then go to Step 17.

INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION

• Inspect variable valve timing control system operation.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF, L5].)

• Does variable valve timing control system work properly?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to inspection results, then go to Step 17.

INSPECT FUEL INJECTOR OPERATION

• Remove the fuel injector.

• Inspect the fuel injector (resistance, injection amount).

(See FUEL INJECTOR INSPECTION [L8, LF, L5].)

• Is the fuel injector normal?

Yes

Go to the next step.

Replace the fuel injector, then go to the next step.

(See FUEL INJECTOR REMOVAL/INSTALLATION [L8, LF, L5].)

VERIFY TROUBLESHOOTING OF DTC P2177:00 COMPLETED

• Make sure to reconnect all disconnected connectors.

• Clear the DTC from the PCM memory using the M-MDS.

• Perform the KOER self-test.

(See KOEO/KOER SELF TEST [L8, LF, L5].)

• Is the DTC P2177:00 present?

Yes

Replace the PCM, then go to the next step.

(See PCM REMOVAL/INSTALLATION [L8, LF, L5].)

Go to the next step.

VERIFY AFTER REPAIR PROCEDURE

• Perform the “AFTER REPAIR PROCEDURE”.

(See AFTER REPAIR PROCEDURE [L8, LF, L5].)

• Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [L8, LF, L5].)

Troubleshooting completed.