P1291

[Lone Watie]

Every now and then I throw a

P1291 - No Temperature Rise Seen From Intake Air Heaters

like this evening on way to work, only on start up. I usually just reset the CEL and go on my way, but curious if anyone has experience with this code, or what I could check. I'm guessing the intake grid heaters, but they seem to work okay, voltage draw when cold, , wait to start, etc.

Thanks.

Edited February 20, 2010 by Lone Watie

[Mopar1973Man]

Let me correct your error code... P1291 (M) No Temperature Rise Seen From Intake Air Heaters. Problem detected in intake manifold air heating system. Is your grid heaters actually working? I would double check the fusable links in the battery lines and then double check the relays to be sure the voltage is passing the solenoids (bad internal contacts). Then I would phyiscally check the grid heater for a broken elements...

[Lone Watie]

I forgot about the link on your web site for OBDII, and quickly pulled that description for a 1291 off a google search. Anyway, I'll check that stuff out as you suggested. I think something may have got wet today. I cleaned the bottom of engine and tranny with some degreaser and was spraying a lot of water from the bottom up, so maybe got something wet. I'm pretty sure the grids are working, as I see the usual voltage drop in the morning when they're cycling, but I'll check all that stuff out anyway. Thanks.

[Lone Watie]

Are the intake air heater gaskets reusable? Just checking before I open them up and get stuck up the creek. Thanks. Also, any tips/how to's on checking the relays?

[Mopar1973Man]

Are the intake air heater gaskets reusable?

Might be re-useable. Mine are graphite gaskets which are very re-useable... But I've seen several stockers with paper style gaskets which are not and typically tear as you remove the heaters...

Just checking before I open them up and get stuck up the creek. Thanks.

So pick up a set if your smart...

Also, any tips/how to's on checking the relays?

Simple enough just take a test light and see if there is power at the 2 heavy leads on the grid heaters when the key is turn on for a cold start... The test light should go out after the WAIT TO START goes out as well.

Another way of testing...

http://forum.mopar1973man.com/showthread.php/1082-Grid-heater-temp..?highlight=grid+heater

[Lone Watie]

I like ISX's way, thanks...