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, 201015 yr by Lone Watie

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...

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.

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?

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

I like ISX's way, thanks...