DEF system questions -2014 duramax

[Willcoc]

1. How much DEF should I be using. Used about 2.5 gallons in 700 miles. I think this is high based on what I have read but not sure where to look for a problem.
2. I had a P21dd - reductant heater 1 current low code. Cleared it and has not returned but only been 1 day. Not able to find much about what part would be the issue if this code returns. Looked at the gmdirect parts breakdown and it does not list the heater.

Suggestions or ideas?

[a5150nut]

Found this on another site http://www.cruzetalk.com/forum/201-chevy-cruze-diesel-technical-discussion/122082-2014-ctd-error-code-p21dd-emission-reductant-tank-heating-system-urea.html

[Kennedy]

My suggestion is to drive until it says it is low. Then add 5 gallons and drive until it nags again.

I had very good luck with the Terra Caire fluid. Most of the "help!" topics tat I see are from Blue or Peak so I always avoided these brands.

[Willcoc]

Cleared the code on Thursday evening. Drive all but Saturday and has not returned. I had seen the Cruze info but that is all so far.

Filled the def tank at a Speedway station. Put in 5 gallons and we will see how long it lasts. Kind of a pain since the hose had to be stretched across the engine compartment as I did not go into the station backwards.

Good to know that others have not had this issue.

Will update if the code returns

[DmaxMaverick]

We had a similar issue with our 2014 Cruze (more details to follow, in the Cruze Diesel forum). Started a few months ago with reductant heater low, high, then no voltage. Code(s) similar to yours, then finally a recurrent P205B. Dealer updated the PCM calibration (per GM bulletin) and it went away for a week. Came back, took it in, and they replaced the reductant tank sub-tank (where the heater is). It's been more than a month, and it seems fixed Simple repair, really. About an hour of labor and a total of $160 parts, all warranty, of course. I'm not yet familiar with the truck reductant system, and it may be less accessible than our car. Our system is in the trunk, where the spare tire would be, if it had one. The entire system is easily accessible.

Just for a vague reference, the Cruze uses about 5 gallons DEF over 8-10K miles, with a lifetime average of 40+ MPG. If usage is relative to economy, 2.5 gallons in 700 miles is ridiculously too much. The whole concept is still too new to know what is supposed to be what, but that just sounds really wrong, even with an average of ~15 MPG.

Keep the dealer informed of the issue, and take it in as necessary. It should be under warranty for a long while yet.

[Willcoc]

Drove the truck 5 of the last 7 days and the code came back in the middle of the day. Temp was 55 at the time so not sure what temperature the heater turns on at but has been cooler than this most days. Was raining at the time but doubt that would have an effect. Cleared the code again.
Unless GM has a really extended warranty, with 152,000 miles, it won't see a dealer for repairs.

[DmaxMaverick]

Yeah, that's a lot of miles. Your emission system warranty is probably used up, but it's free to ask.

It isn't that the heater is trying to engage at 55. The system does routine circuit checks every so many warm-up and/or start cycles. Our issue started during summer, so the actual outside temp wasn't in play, at all.

[Willcoc]

The ses light returned after 3 starts. Have not stopped by the check the code. Time for more research....