Tech Tips > January 2008

You may come across a 2001 Dodge Dakota with a 4.7L that
may have erratic fuel trims with a rich operation. This
may be accompanied by O2 sensor codes and lack of O2
operation. Do not be so quick to replace the O2 sensors.
Inspect the O2 sensors and ECM for oil intrusion caused
by a leaky P/S switch that will literally pump P/S fluid
through the engine harness back into the ECM and down
into the O2 sensors. The ONLY fix here is to replace
the ECM and the ENTIRE engine harness.
 

You may come across a 2002 Ford E250 with a 5.4L that
will not start due to no fuel pump operation. After
performing a circuit check you will discover that
there is no power getting to the fuel pump. The info
you are using will not help you to find the relay
because it is buried literally inside the driver
fuse/relay panel soldered to the circuit board.

*These circuit board relays have a high failure
rate and the only resolve is to replace the entire
panel.