Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Won't Start, Only Showing HVAC Codes

Hi folks. My van lost power while I was driving down the highway. It cranks, but won’t start. I can hear the fuel pump engaging, so I don’t think that’s the cause.

The only codes my scanner is showing are all HVAC codes: b0408, b0268, b0248, b0238.

I understand that the engine needs airflow, but I was under the impression that HVAC codes just related to cabin A/C, heat, etc.

Could one of those codes be related to why the car won’t start? I’m very grateful for any help or suggestions. Thanks.

year,make,model, and mileage please.

2007, Pontiac Montana, 345,267 km.

A bit of an update. It has fuel, it has spark. We haven’t test compression yet.

The other question is does it have enough fuel, and is the spark coming at the proper time? I’m wondering if maybe your timing chain jumped a tooth or two.

When it lost power on the highway, is that just the engine, or did all the dash lights/etc go out too?

Fuel appears to be good. No idea about the timing yet. That’s one of the things we’re checking today.

Just the engine died. Everything electrical continued working.

Okay, no more mobile mechanics for me. They’re probably fine for really minor repairs, oil changes, tire swaps, etc., but my experience has left me with a bad taste in my mouth.

The second guy was positive it was the battery, even after first guy got spark. He tested the battery, and it did indeed appear to be dead. New battery…no results. He then tried to tell me it was out of gas. Again, after the first guy determined it had fuel. Solely to humour him, I filled up my jerry can and put some more gas in. More gas…no results.

The next step was a compression test, according to him. This would cost a lot, as a mobile mechanic can’t do anything else when they’re hanging out in your driveway. Note that I don’t think he was insisting on this to bump up the bill. He kept trying to convince me not to do it, but to just junk the car and get a new one instead.

Straight up, there are times that this is the best thing to do. This was absolutely not one of those times, and wouldn’t have been even if it did need a compression test and new head gasket.

I decided not to go with them anymore, and started calling local mechanics. Every single one of them asked the exact same thing: “Why do you think you need a compression test? You probably don’t need a compression test.” Every. Single. One.

Eventually went with a guy who said something like: “Bring it in for a half-hour diagnostic, and I bet I can figure out what the trouble is.” He turned out be correct. He figured it out, ordered some parts, and I was back on the road the next day.

Guess what the problem turned out to be? Spark plugs and wires! Cheap, cheap, cheap. The bill became much bigger than it should have been because…

a) I wanted to give the mobile guys a shot after failing to fix it myself. This is clearly my fault.
b) The mobile guys don’t really seem to know what they’re doing. This is also clearly my fault for believing they did.

I guess the thing to keep in mind is that there are quite a few problems that there will never be a code set for them. So yeah back to basics.