E39 / P0171 00
Read the instructions below then
start the fault diagnostic procedure.
Symptom: Malfunction Indicator Lamp
The engine may stop after starting, run unevenly and misfire.
Long Term Fuel Trim Multiplicative. Max Value, Air/Fuel too Lean.
Fault symptom
Malfunction Indicator Lamp
The engine may stop after starting, run unevenly and misfire.
On-board diagnosis
Type of diagnosis:
Enable criteria:
| The engine has started and lambda control is active. |
| A multiplicative adaptation is carried out. |
Fault criteria:
| The multiplicative adaptation factor exceeds 30%. |
Diagnostic help
Diagnosis regards:
| Checking air/fuel ratio. With this DTC, the engine will be getting too much air or too little fuel. |
| A crankcase ventilation leak may be one reason as to why a DTC is set. Check crankcase ventilation function before starting regular troubleshooting. |
Functions in the diagnostic tool related to the fault:
| • | Multiplicative Fuel Adaptation |
| • | Requested Fuel Rail Pressure |
| (See also description of readings/activations in diagnostic tool) |
