FMF MX

Hey all -

That infernal check engine light again..This time its the two codes above..1293 is a companion code, (whatever that is) and 1291 has something to do with the engine air intake heater. Anyone got any ideas on how to clear/fix? I tried the fuses, they're fine, also checked the connections, but its still there... I'm getting ready for a roadtrip, don't want this hanging over my head if I can help it..Thanks in advance for any assistance..

phox_mulder

Are you sure it's 1291 and 1293 and not 1691/1693 ?

I show
P1291 No Temperature Rise Seen From Intake Air Heaters
P1293 CNG Pressure Sensor Voltage Too Low

Have you recently converted to cleaner burning Compressed Natural Gas?

However, 1691 and 1693 make more sense.


P1691 Fuel Injection Pump Controller Calibration Failure

P1693 DTC Detected In ECM Or PCM (the companion code)


phox

FMF MX

I'm so ignorant...Yes, its p1693, but 1291 is correct...any idea how to fix them?

phox_mulder

Ok, grid heaters.

How long is your Wait to Start staying on?

First thing to come to mind is the relays for the grid heaters.


phox

FMF MX

It stays on for 6 sec or so when cold, less when warm. But I don't hear that "click" when it goes out like I used to. What should I be checkin?

phox_mulder

That "click" would indeed be the relay(s).

Sorry, I really don't know where they are.
PDC? under the hood?

They should be connected directly to the battery though, by a pretty stout piece of wire,
they draw some pretty hefty amps.


phox

FMF MX

Well, in the underhood fuse box, there is a row of 4 relays, all of them over 50 amps..Their about 1 inch square, I switched the engine heater one with the one for towing, but no change..Is these the relays they are referring to?

high country

follow the wires, the the big wires from the intake manifold over to the ds fender you will see the big relay there.

FMF MX

Alright, I'll give it a go..thanks.