Codes P0306 and P0174 appeared after radiator hose blew

You may have an issue that is related to this incident but this is a cylinder 6 misfire and a lean exhaust code.

Here is a guide that will help with a misfire issue:

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Next we need to evaluate for a lean condition. Here is a guide that will help with this:

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

I would suggest starting with just swapping the spark plug, and injector with another cylinder one at a time, and see if the misfire moves to that cylinder.

Also, you need to inspect the vehicle for coolant in any of these connectors for the coil and injector if it sprayed on the engine.

Lastly you will need to look for a vacuum leak.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let's run through this material and let us know if you have questions. Thanks

Hi,

The codes you have are likely caused by the hose. However, they are not being set by the alternator. I suspect that either high-pressure water damaged something or disconnected a hose or wire.

The P0306 indicates a misfire on cylinder 6. If the coil or wires were saturated with the hot coolant, that may have caused the misfire. If you look below, I attached a pic of the coil. There will be six spark plug wires coming from it and each one goes to a different cylinder. I highlighted where number 6 is located. Unplug it to make sure it isn't damaged and properly attached. If it is, follow that spark plug to the number 6 spark plug to make sure nothing has caused it damage.

As far as the P0174, that indicates a lean fuel mixture. This is usually the result of an engine vacuum leak. There are vacuum hoses that could have been disconnected or damaged as well. If that is the case, unmetered air gets into the engine and causes this code to set.

Here is a link that explains how to locate and repair an engine vacuum leak:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know if this helps. Pic 1 below is the coil pack (top front of the engine). Pic 2 shows the location of cylinder 6. Make sure the spark plug wire between the coil and the spark plug is connected and not damaged.

Let me know what you find or if you have other questions. Also, let me know how long ago this happened and if the vehicle has had long enough for everything to dry.

Take care,

Joe