Volvo

The preheat function is used to warm up the inlet air during cold conditions both before and after cranking to make the starting easier and better for the environment at very low temperatures. This diagnostic trouble code (DTC) detects a faulty preheat function.

Conditions for diagnostic trouble code (DTC):
1) Preheating requested
2) The voltage at pin A14.EB:7 is less than 29?% of the battery voltage

Observable symptoms
1) Intake air heater (IAH) does not function
2) White smoke at cold start
3) Difficult to start in extreme cold

Probable cause
1) Wiring harness
2) Connector
3) Intake air heater (IAH) relay

The preheat function is used to warm up the inlet air during cold conditions both before and after cranking to make the starting easier and better for the environment at very low temperatures. This diagnostic trouble code (DTC) detects a faulty preheat function.

Conditions for diagnostic trouble code (DTC):
1) The voltage at pin A14.EB:14 is more than 91?% battery voltage

Diagnostic operating conditions
1) Ignition key in ON position

Observable symptoms
1) Intake air heater (IAH) relay may be constantly activated
2) High intake air temperature (IAT)
3) High current consumption
4) Power loss
5) Low battery voltage

Probable cause
1) Wiring harness
2) Connector
3) Intake air heater (IAH) relay

Conditions for diagnostic trouble code (DTC):
1) Preheating requested
2) The voltage at pin A14.EB:14 is less than 29?% of the battery voltage

Observable symptoms
1) Intake air heater (IAH) does not function
2) White smoke at cold start
3) Difficult to start in extreme cold

Probable cause
1) Wiring harness
2) Connector
3) Intake air heater (IAH) relay

The preheat function is used to warm up the inlet air during cold conditions both before and after cranking to make the starting easier and better for the environment at very low temperatures. This diagnostic trouble code (DTC) detects a faulty preheat function.

Conditions for diagnostic trouble code (DTC):
1) The voltage at pin A14.EB:14 is less than 29?% of the battery voltage

Diagnostic operating conditions
1) Ignition key in ON position

Observable symptoms
1) Preheating does not function
2) Difficult to start in extreme cold

Probable cause
1) Faulty connection
2) Fusible Link
3) Wiring harness
4) Intake air heater element

This signal is sent from the (VECU) Vehicle Electronic Control Unit to the Cluster to present the actual vehicle speed. It is also used by the maximum speed limitation. The maximum speed limit can vary depending on customer option.

Conditions for diagnostic trouble code (DTC):
1) No vehicle speed available to VECU

Observable symptoms
1) None

Probable cause
1) Vehicle speed sensor
2) Vehicle Control Unit (VECU)

This signal is sent from the (VECU) Vehicle Electronic Control Unit to the Cluster to present the actual vehicle speed. It is also used by the maximum speed limitation. The maximum speed limit can vary depending on customer option.

Conditions for diagnostic trouble code (DTC):
1) This fault can be caused by an ABS/EBS wheel speed calibration error, it is important to exit this fault tracing and check the ABS/EBS wheel speed calibration before continuing
2) Vehicle speed deemed inaccurate by VECU

Observable symptoms
1) Speedometer shows no vehicle speed

Probable cause
1) Vehicle speed sensor
2) Vehicle Control Unit (VECU)
3) ABS/EBS Wheel Speed Calibration Error

This signal is sent from the (VECU) Vehicle Electronic Control Unit to the Cluster to present the actual vehicle speed. It is also used by the maximum speed limitation. The maximum speed limit can vary depending on customer option.

Conditions for diagnostic trouble code (DTC):
1) Implausible sensor signal

Observable symptoms
1) Functions that are dependant on the vehicle speed information can be limited or shut off
2) Speedometer shows no vehicle speed

Probable cause
1) Tachograph
2) Vehicle speed sensor

This signal is sent from the (VECU) Vehicle Electronic Control Unit to the Cluster to present the actual vehicle speed. It is also used by the maximum speed limitation. The maximum speed limit can vary depending on customer option.

Conditions for diagnostic trouble code (DTC):
1) Signal unavailable or not regularly updated

Observable symptoms
1) Engine de-rated

Probable cause
1) Vehicle speed sensor
2) Vehicle Control Unit (VECU)

The pedal message is used to calculate fuel injection.
The J1587 and J1939 serial data lines are used as the standard communication link for on-board vehicle instrumentation, off-board service diagnostics and fleet management.
The (VECU) Vehicle Electronic Control Unit is linked to the Engine Control Module (ECM) via these data lines.

Conditions for diagnostic trouble code (DTC):
1) The accelerator pedal is not connected to the VECU

Probable cause
1) Accelerator pedal
2) Vehicle Control Unit (VECU)