P1646 - Jaguar
Type Powertrain - Manufacturer Controlled DTC - Manufacturer Controlled
Description
Fuel pump relay 2 - malfunction
Cause
Wiring, fuel pump relay

Where do I start?

 

It's not that meaning. Consult the forum and/or codes PDF and/or JTIS. (It's an O2 code but those sources give you all the possible causes as well.)

What was the (faulty) tool that gave you that bad meaning?

 

I was using the elm327

 

The elm327 is basically hardware and does NOT provide any meanings. It must be the crappy software you used with it... which was?

 

Basic scanners can give misleading results with Jaguars but generic code lookups can be even more dangerous! Here is the Jaguar extract for P1646:



If the vehicle runs, you can reasonably ignore ECM failure as a possible cause and concentrate on the HO2 Sensor.

Graham