Trouble codes P1478, P1487 and P1498

  • 2.5L
  • V6
  • 157,000 MILES
I have a CEL light that I cannot turn off. I have replaced everything that coded. The codes are P1478, P1487, and P1498.

Why can't I clear the light with a code reader? And no matter what I do, I am still having issues with it stalling and acting like it's out of gas. I have replaced the fuel pump relay, the automatic shutdown relay, I have replaced the fuel pump I have replaced the ECM I have replaced the battery and I have replaced the crankshaft position sensor and the fuel filter what else can I do what am I missing?
Do you
have the same problem?
Friday, October 23rd, 2020 AT 6:16 PM

1 Reply

P1478 - Battery Temp Sensor Volts Out of Limit
P1487 - Hi Speed Rad Fan CTRL Relay Circuit
P1498 - Voltage Problem In EGR Valve Position Sensor Circuit

Here's the list of code definitions:

I come up with codes that don't involve stalling or the numerous parts you listed. By now you probably figured out that throwing random parts at the problem is the least effective and most expensive way to diagnose a problem. Hopefully we can change that.

The first thing you have to understand is when a sensor or other part is referenced in a fault code, that never ever means that part is defective or must be replaced. Those parts are only responsible for that code about half of the time. First we have to rule out wiring and connector terminal problems, or mechanical problems associated with that part before we spend our customer's money on an unneeded part.

Lets start with more details on the stalling problem. Are there any conditions that seem to be common to each event? Is there anything you can do to cause it to occur or to keep the engine going a little longer? How long after you start the cold engine does this occur? If you can keep it in the stalled state, start by checking for spark. You probably don't need it, but for the benefit of others researching this topic, here's a link to an article on checking for spark:

If spark is okay, the next step is going to be to connect a fuel pressure gauge and place it under a wiper arm so you can see what happens when the stalling occurs.

When you replaced the fuel pump, did you replace just the pump and motor or the entire housing assembly? Specifically, the housing has a pick-up screen attached to it. Did that get replaced?
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Friday, October 23rd, 2020 AT 6:42 PM

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