Hyundai Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #1
This morning was cold (-20 Celsius), the car started fine. I drove for 20 minutes then turned it off for 15 minutes, when I came back to start the engine, the immobilizer light didn't show and the car obviously didn't start but was cranking. After a few attempts at inserting the key, the immobilizer light came on and the car started fine.


It only happens a few times every winter when it's really cold outside, the engine is hot but the inside of the car is not completely warmed. Can it be condensation on the contacts of the immobilizer antenna? Is there something I could do to solve this problem for good?


The dealer already replaced the main relay 2 years ago but it never solved the problem.


I now have the P0685 (ECM/PCM Power Relay Control Circuit /Open) code showing but the MIL light is off. Can this code be related to the immobilizer issue?
 

·
Registered
Drives : Nissan NV200 Flies : Rans S6ES
Joined
·
16,096 Posts
When you switch the ignition on and notice that the immobilizer light isn't on, is the CEL illuminated?
 

·
Registered
Drives : Nissan NV200 Flies : Rans S6ES
Joined
·
16,096 Posts
So the CEL switched off and the engine wasn't running? That seems to suggest your non start isn't an immobilizer issue. Neither does the trouble code.

Having said that, there are some known issues with the connector between the ring antenna and the immobilizer antenna amplifier. It seems a layer of oxidation/corrosion can build up on the terminals of the connector and prevent the very small voltages of the key signal from passing. The simple fix is to cut the ring antenna wires on either side of the connector and solder the wires, removing the connector and the high resistance caused by the oxidation from the circuit. There are a few posts on the forum from folk who have confirmed that has cured their intermittent non start issues.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #5
Ok, thanks, I will try this solution as soon as it gets warmer.


For the CEL, to be honest I don't remember if it stayed lit or not during the whole time the key was in. I looked at all the lights only once to make sure they were all on and the rest of the time I was looking at the immobilizer light.


The P0685 code and the symptoms I described were exactly the same when the dealer replaced the main relay and it didn't fix the problem.
 

·
Registered
Joined
·
16 Posts
I am having the same problem with my 2007 santa fe. It starts up fine on super cold days then I drive it for about 20 mins and park outside a store and a half hour later I can't start it. The immobilizer icon lights up everytime I try to start it but even though it turns over for a few seconds it won't "Catch". Did soldering the wires work for you?
 

·
Registered
Joined
·
14 Posts
Discussion Starter #7
I am having the same problem with my 2007 santa fe. It starts up fine on super cold days then I drive it for about 20 mins and park outside a store and a half hour later I can't start it. The immobilizer icon lights up everytime I try to start it but even though it turns over for a few seconds it won't "Catch". Did soldering the wires work for you?
Sorry I didn't see your post before. I can't tell if it worked because I never used the car in a really cold day since then.
Although I don't think it is the same issue since your immobilizer light comes on while mine was off.
 

·
Banned
Joined
·
7,037 Posts
This morning was cold (-20 Celsius), the car started fine. I drove for 20 minutes then turned it off for 15 minutes, when I came back to start the engine, the immobilizer light didn't show and the car obviously didn't start but was cranking. After a few attempts at inserting the key, the immobilizer light came on and the car started fine.


It only happens a few times every winter when it's really cold outside, the engine is hot but the inside of the car is not completely warmed. Can it be condensation on the contacts of the immobilizer antenna? Is there something I could do to solve this problem for good?


The dealer already replaced the main relay 2 years ago but it never solved the problem.


I now have the P0685 (ECM/PCM Power Relay Control Circuit /Open) code showing but the MIL light is off. Can this code be related to the immobilizer issue?
Yes but focus on the PCM.

Your problem is likely a connection issue in the power or ground circuits of the PCM. The cold will contract the metal contacts of the pins of connectors, grounds, splices ect...and during the warming (expansion) of the slightly problematic area the power/ground connection is lost. After time the connection will mate again. You'll need to follow the diagram for the power and ground circuits of the PCM. Clean all grounds and check pin tension on the PCM (this is critical). Pin tension is a very common problem with temperature related failures.
 
1 - 8 of 8 Posts
Top