Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0139 [BP, BP WITH TC] DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
1		No	Record FREEZE FRAME DATA on repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Check for related Service Bulletins 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 STORED DTCS Turn ignition key to OFF, then start engine. Verify pending code and/or stored DTCs using the WDS or equivalent. Is the following DTC also present?--P0442, P0443, P0455, P0037 or P0038 with P0139	Yes	Go to appropriate DTC troubleshooting procedures, then go to Step 14. (See DTC TABLE .)
3		No	Go to the next step.
4	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA Is DTC P0139 on FREEZE FRAME DATA?	Yes	Go to the next step.
4		No	Go to troubleshooting procedures for DTC on FREEZE FRAME DATA. (See DTC TABLE .)
5	VERIFY CURRENT INPUT SIGNAL STATUS Warm up engine. Access O2S12 PID using the WDS or equivalent. Check PID under following accelerator pedal conditions (in PARK (AT), NEUTRAL (MT)). More than 0.4 V when suddenly depressing accelerator pedal (rich condition) Less than 0.4 V just after release of accelerator pedal (lean condition) Is PID reading okay?	Yes	Go to Step 8.
5		No	Go to the next step.
6	INSPECT INSTALLATION OF REAR HO2S Check if HO2S (rear) is loosely installed. Is sensor installed securely?	Yes	Go to the next step.
6		No	Retighten sensor, then go to Step 14.
7	INSPECT GAS LEAKAGE FROM EXHAUST SYSTEM Visually check if any gas leakage is found between exhaust manifold and HO2S (rear). Is there gas leakage?	Yes	Repair or replace any faulty exhaust parts, then go to Step 14.
7		No	Replace sensor, then go to Step 14.
8	INSPECT LONG TERM FUEL TRIM Access LONGFT1 PIDs. Compare it with FREEZE FRAME DATA (FFD) recorded at Step 1. Is it below FFD value?	Yes	Engine is driven under rich condition. Go to the next step.
8		No	Engine is driven under lean condition. Go to Step 14.
9	INSPECT FUEL LINE PRESSURE (Excessive fuel line pressure) Start engine. Inspect fuel line pressure while engine running. (See FUEL LINE PRESSURE INSPECTION .) Is fuel line pressure within 370-420 kPa {3.7-4.3 kgf/cm2, 53-61 psi}?	Yes	Go to Step 13.
9		No	Go to the next step.
10	INSPECT FUEL PUMP MAXIMUM PRESSURE Perform fuel pump maximum pressure test. (See FUEL PUMP (FP) INSPECTION .) Is fuel pump maximum pressure less than 637 kPa {6.5 kgf/cm2, 92 psi} ?	Yes	Replace pressure regulator, then go to step 14.
10		No	Inspect fuel pump circuit for open circuit or poor connection. Repair or replace suspected circuit. If circuit is okay, replace fuel pump. Then go to Step 14.
11	INSPECT FUEL LINE PRESSURE (Low fuel line pressure) Start engine. Inspect fuel line pressure while engine running. (See FUEL LINE PRESSURE INSPECTION .) Is fuel line pressure within 370-420 kPa {3.7-4.3 kgf/cm2, 53-61 psi} ?	Yes	Go to Step 13.
11		No	Go to the next step.
12	INSPECT FUEL LINE FROM FUEL PUMP TO FUEL DELIVERY PIPE Visually inspect fuel line for any leakage. Is any fuel leakage found?	Yes	Replace suspected fuel line, then go to Step 14.
12		No	Inspect fuel filters for following: Restriction or clogging at fuel filter (high-pressure) Foreign material or stain inside fuel filter (low-pressure) Perform following actions as result. If restriction or clogging is found at fuel filter (high-pressure), replace fuel filter (high-pressure). If foreign material or stain is found inside fuel filter (low-pressure), clean fuel tank and fuel filter (low-pressure). If all items above are okay, go to the next step.
13	INSPECT SEALING OF ENGINE COOLANT PASSAGE WARNING: Removing radiator cap when radiator is hot is dangerous. Scalding coolant and steam may shoot out and cause serious injury. When removing radiator cap, wrap a thick cloth around and turn it slowly. Remove radiator cap. Implement procedure to bleed air from engine coolant, then idle engine. Are there any small bubbles, which makes engine coolant white at the filler opening? NOTE: Large bubbles are normal since they remain air coming out from engine coolant passage.	Yes	Air gets in from poor sealing on head gasket or other areas between combustion chamber and engine coolant passage. Repair or replace faulty parts, then go to the next step.
13		No	Go to the next step.
14	VERIFY TROUBLESHOOTING OF DTC P0139 COMPLETED Make sure to connect all disconnected connectors. Turn ignition key to ON (Engine off). Clear the DTC from the memory using the WDS or equivalent. Start engine. Run OBD-II DRIVE MODE 1 and 3. (See OBD-II DRIVE MODE .) Stop vehicle and access ON BOARD SYSTEM READINESS TEST to inspect DRIVE MODE completion status. Verify RFC changes to YES for OXYGEN SENSOR. If not, run DRIVE MODE again. Access DIAGNOSTIC MONITORING TEST RESULTS. Verify following TEST # values: 10: 01: 12, 10: 02: 21 or 10: 03: 21 Are they all below MAX value?	Yes	Go to the next step.
14		No	Replace PCM, then go to the next step.
15	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE ". (See AFTER REPAIR PROCEDURE .) Is any DTC present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
15		No	Troubleshooting completed.