Car will not always start

Hi,

Many things can cause this. If you mean the starter doesn't engage, the most common cause are dirty or loose battery terminals. I would start by checking that. Take a look through this link:

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

Next, when it refuses to start, shift to neutral and try it. If it starts in neutral, you may have a problem with the neutral/park safety switch.

If everything looks good with the terminals, it becomes more if an issue of checking things. On most cars, there is a starter relay and your's has one to. The engine starting system functions by controlling both starter relay and starter control relay. Both relays are integrated in IPDM E/R. Starter relay is controlled by BCM, and starter control relay is controlled by IPDM E/R on request from BCM. IPDM E/R transmits starter relay and starter control relay status signal to BCM via CAN communication.

I attached a pic below. It shows both relays that are mentioned above. What I need you to do is remove them and make sure there is no corrosion where they plug in to the IPDM (intelligent power distribution module). It is located under the hood of the vehicle.

Here is a link that explains how to test a relay, but my concern is that it is intermittent:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

If everything checks good, then when it refuses to start, you need to check for power at the starter itself. Here is a link that explains how it's tested:

https://www.2carpros.com/articles/starter-not-working-repair

Here are directions for using a test light. Additionally, you will need a helper to perform this test.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

The starter is on the side of the engine and will be facing the radiator. I attached a pic below if what to look for.

I realize this seems like a lot. Please feel free to let me know if you have other questions. Also, if you can think of anything that may help me better diagnose the problem, let me know.

Take care,
Joe