B3781 Chevrolet Astra OBD Code

OBD/2 B3781 error code description and symptoms.

Low Speed Fuel Pump Primary Circuit Malfunction The PCM monitors the low speed fuel pump (LFP) primary circuit output from the PCM.
The test fails if: When the LFP circuit is commanded on (grounded), excessive current draw is detected on the LFP circuit; or when the LFP circuit is commanded off, voltage is not detected on the LFP circuit (the PCM expects to detect VPWR voltage coming through the low speed fuel pump relay coil to the LFP circuit). Open or shorted low fuel pump (LFP) circuit Open VPWR to low speed fuel pump relay Damaged low speed fuel pump relay Damaged PCM An open circuit or short to ground can only be detected with the low speed fuel pump.

Circuit High Input codes like B3781 are mostly caused by defective alternators that develop excessive voltages, although there may be other causes as well, such as short circuits that 'leak' current into a particular system from other, unrelated systems that work on higher voltages. Note that in the case of short circuits that leak power into a control circuit, there is likely to be other, seemingly unrelated trouble codes present along with the code(s) being investigated. Diagnosing a 'high input' code will always involve a thorough testing of the charging system as a first step, followed by measures to isolate the system from all other possible sources of power during resistance, continuity, and reference voltage tests.

B3781 Chevrolet Astra Error Code Repair Process :

For wiper rear motor run relay circuit failure check engine light is perhaps the most troubling of lights because it could mean so many different things, from you didn't screw the gas cap on tightly enough to look out for pistons flying through the hood and into the stratosphere. The easiest way to find out what this light is telling you is to hook your vehicle up to a scan tool. B3781 error code diagnostic tool looks a little like an oversized calculator and plugs into a communication port inside the car. After you instruct it to perform the scan, it speaks wiper rear motor run relay circuit failure with your car's computers to find out exactly what's prompting the light to turn on.

Common Causes of Chevrolet Astra B3781 OBD2 Code

A common cause of code B3781 is the failure of Wiper Rear Motor Run Relay Circuit Failure, but there are several other possible causes as well, such as ;

EVAP canister or fuel tank leaks
Faulty Intake Valve Timing Control Solenoid Valve
Incorrect fuel pressure
Erratic camshaft position due to low oil pressure

B3781 Chevrolet Astra OBD Code

B3781 Chevrolet Astra Error Code Repair Process :

Common Causes of Chevrolet Astra B3781 OBD2 Code

B3781 code for other Chevrolet cars