DTC P0172:00 [MZ-CD 1.6 (Y6) (EURO5 emission level)]

id0102g7934300

DTC P0172:00

Fuel system too rich

DETECTION CONDITION

•  The PCM monitors the lambda value using the A/F sensor. If the A/F sensor lambda value is low, the PCM determines that the fuel system is too rich.

POSSIBLE CAUSE

•  Engine oil deterioration (High amount of fuel mixed in engine oil)

•  Fuel injector malfunction

•  A/F sensor malfunction

•  Open or short circuit between fuel injector and PCM

•  PCM malfunction

DTC P0172:00	Fuel system too rich
DETECTION CONDITION	• The PCM monitors the lambda value using the A/F sensor. If the A/F sensor lambda value is low, the PCM determines that the fuel system is too rich.
POSSIBLE CAUSE	• Engine oil deterioration (High amount of fuel mixed in engine oil) • Fuel injector malfunction • A/F sensor malfunction • Open or short circuit between fuel injector and PCM • PCM malfunction

Diagnostic procedure

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED • Has the FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY • Verify related service repair information availability. • Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. • If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY RELATED PENDING CODE AND/OR DTC • Switch the ignition to OFF, then to ON (engine off). • Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure. (See ON-BOARD DIAGNOSTIC TEST [MZ-CD 1.6 (Y6) (EURO5 emission level)].) • Is the other PENDING CODE/DTC also present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZ-CD 1.6 (Y6) (EURO5 emission level)].)
3		No	Go to the next step.
4	VERIFY ENGINE OIL CONDITION • Verify the engine oil condition (amount, color, smell). (See ENGINE OIL LEVEL INSPECTION [MZ-CD 1.6 (Y6)].) • Is the engine oil condition normal?	Yes	Go to the next step.
4		No	Replace the engine oil, then go to Step 8. (See ENGINE OIL REPLACEMENT [MZ-CD 1.6 (Y6)].)
5	INSPECT FUEL INJECTOR • Inspect the fuel injectors. (See FUEL INJECTOR INSPECTION [MZ-CD 1.6 (Y6)].) • Is there any malfunction?	Yes	Replace the fuel injector, then go to Step 8. (See FUEL INJECTOR REMOVAL/INSTALLATION [MZ-CD 1.6 (Y6)].)
5		No	Go to the next step.
6	INSPECT A/F SENSOR • Inspect the A/F sensor. • Is there any malfunction?	Yes	Replace the A/F sensor, then go to Step 8.
6		No	Go to the next step.
7	INSPECT FUEL INJECTORS CIRCUITS FOR OPEN OR SHORT CIRCUIT • Inspect for open or short circuit between following fuel injector terminals and PCM terminals. ― Fuel injector No.1 terminal A—PCM terminal 3AT ― Fuel injector No.1 terminal B—PCM terminal 3AP ― Fuel injector No.2 terminal A—PCM terminal 3AV ― Fuel injector No.2 terminal B—PCM terminal 3AR ― Fuel injector No.3 terminal A—PCM terminal 3AU ― Fuel injector No.3 terminal B—PCM terminal 3AQ ― Fuel injector No.4 terminal A—PCM terminal 3AS ― Fuel injector No.4 terminal B—PCM terminal 3AO • Is there any malfunction?	Yes	Repair wiring harness for a possible open or short circuit, then go to the next step.
7		No	Go to the next step.
8	VERIFY THAT DTC P0172:00 TROUBLESHOOTING IS COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the M-MDS. • Run the vehicle under the FREEZE FRAME DATA stored condition. • Is the same DTC present?	Yes	Repeat the inspection from Step 1. • If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZ-CD 1.6 (Y6) (EURO5 emission level)].) Go to the next step.
8		No	Go to the next step.
9	VERIFY AFTER REPAIR PROCEDURE • Perform the After Repair Procedure. (See AFTER REPAIR PROCEDURE [MZ-CD 1.6 (Y6) (EURO5 emission level)].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZ-CD 1.6 (Y6) (EURO5 emission level)].)
9		No	DTC troubleshooting completed.