P1637

Read the instructions below then start the fault diagnostic procedure.

Symptom: CHECK ENGINE. Loss of performance.

P1637

Fault symptoms

•	CHECK ENGINE.

•	Loss of performance.

On-Board Diagnostics

Type of diagnosis:

-	Continuous.

Enable criteria:

-	Ignition ON.

-	Battery voltage should be 10.2-15.8 V.

Fault criteria:

-	Voltage on outputs (7, 98) exceeds 4.1 V for more than 0.3 s.

Dependents:

-

None.

System reaction to a fault:

-	EGR and boost pressure control switched off.

OK report:

-	Voltage on outputs falls below 4.1 V for more than 0.3 s.

Fault handling: (See section Fault handling III, other emissions-related components and functions for more information)

-

Type III.

Diagnostic help

The diagnosis concerns an electrical fault on the voltage output to:

- Accelerator pedal position sensor

- EGR solenoid valve

- Charge air pressure sensor

- Position sensor guide rails, turbocharger

- Fuel pressure sensor, fuel rail

Functions in the diagnostic tool related to the fault:

-	Read value: Charge Air Absolute Pressure, Charge Air Pressure Sensor, Actual VNT Position, EGR Valve Position, EGR Valve Position Sensor, Fuel Pressure, Fuel Pressure Sensor, Pedal Position Sensor 1

Checking the wiring

Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.