OBD and Air Supply
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Information on diagnostics
The diagnostic trouble codes P0097, P0102, P0400, P0172 and P0506 can be displayed on an on-board diagnostic system (OBD). They indicate a fault within the air supply system of the vehicle. You can find out the causes of these diagnostic trouble codes and what you can do to resolve the issue here.
| PIERBURG PRODUCTS | ON-BOARD DIAGNOSTICS |
| 01 Activated carbon filter valve | 12 Engine control unit |
| 02 EGR valve | 13 Malfunction indicator lamp (MIL) |
| 03 Electric drive module | 14 Diagnostic plug |
| 04 Intake manifold/variable intake manifold | 15 OBD data scan tool |
| 05 Intake manifold pressure sensor | |
| 06 Throttle valve/regulating throttle | |
| 07 Air mass sensor (LMS) | |
| 08 Recirculating air valve | |
| 09 Pressure transducer (for actuating the VTG turbocharger) | |
| 10 Air filter (Kolbenschmidt) | |
| 11 Idle controller |
FROM PRACTICAL USE
FINDING AND REMEDYING FAULTS
| DIAGNOSTIC TROUBLE CODE | P0097 | P0102, P0400 |
| DISPLAYED FAULTS | Intake air temperature sensor – input signal too low • Plausibility check delivers incorrect reference values • Temperature sensor on air mass sensor is defective • Intake air temperature sensor faulty |
Mass air flow meter or air flow meter – input signal too low/exhaust gas recirculation – flow rate malfunction • Air mass sensor faulty • Stuck/carbonised EGR valve is always open • Basic setting of EGR valve not performed |
| NEXT STEPS/ POSSIBLE REMEDIES | • Check air mass sensor, replace if defective • Check intake air temperature sensor, replace if necessary |
• Check power supply to mass air flow meter and EGR valve • Check mass air flow meter, replace if defective • Check EGR valve: - If the EGR valve is always open, exhaust gas is recirculated permanently - If the EGR valve is stuck, replace and find out the causes of the sticking • Once a new EGR valve has been installed: perform basic setting (engine tester) |
| DIAGNOSTIC TROUBLE CODE | P0172 | P0506 |
| DISPLAYED FAULTS | Mixture too rich • Activated carbon filter solenoid valve stuck (permanently open): Fuel-enriched air from the activated carbon filter is drawn into the intake air system • Diaphragm of the pneumatic fuel pressure regulator leaking: Fuel is drawn into the intake air system through the vacuum line • Stuck/carbonised EGR valve is always open |
Idle control – engine speed below set-point value • Idle controller soiled/stuck • Incorrect input signals arriving from the engine control unit • Throttle valve stiff/stuck |
| NEXT STEPS/ POSSIBLE REMEDIES | • Activated carbon filter solenoid valve, replace if necessary • Check fuel pressure regulator, replace if necessary • Check EGR valve: - If the EGR valve is always open, exhaust gas is recirculated permanently - If the EGR valve is stuck, replace and find out the causes of the sticking |
• Check idle controller using an oscilloscope • Replace stuck/carbonised idle controller • Read out input signals of the idle controller using the diagnostic tester • Replace stuck/carbonised throttle valve and find out the causes of the sticking |
