Hey im new to this forum I need help with my infiniti i35 it cranks but no start. I had fuel pump changed and still. I got the codes read and got p1612. My mechanic told me its a nats issue I noticed my security light stays on solid while in the on position and while cranking. He told me to get the key reprogrammed I only have one key since I got the car. I brought my key to a local locksmith to have the key checked before doing anything so after he put the key in the machine he said its a weird code or something and said he might be able to do it but it can be something else with nats. I dont know wat else it can be all fuses/relays are good car was good before this. I read something about antenna ring, immu, and ecm how can I diagnose these?
Thanks to anyone willing to help in advance.

 

If you're sure you've checked all fuses all right ( 15A fuse, #59 in the fuse box under the hood; and 15A fuse #20 in the box under the dash), then your ICU (Immobilizer Control Unit) has probably malfunctioned. It is located on the key cylinder. The part# is 28590-C9901. Once it's replaced then the key will have to be reprogrammed. That's an easy process that can be done by the locksmith. It may have been damaged by a short, so be sure to check all your electrical connections (fuse-ICU-ECM).

 

P1610 INFINITI - Lock Mode

Possible causes
Faulty or not programmed ignition key
Faulty IMMU
Faulty Engine Control Module (ECM)

This code is usually triggered when a not registered or damaged key is used to start the engine. When the starting operation is carried out five or more times consecutively with the same unregistered key, the system will lock. If the problem occurs try disconnecting the car battery for about 30 minutes and then try starting the engine with a known registered key. If the problem persists you have to have the dealer erase the code and reprogram the keys again.

If problem persists after disconnecting the car battery, try the following:

ESCAPE FROM LOCK MODE
1. Turn ignition switch OFF.
2. Turn ignition switch ON with registered key. (Do not start engine.) Wait 5 seconds.
3. Return the key to OFF position.
4. Repeat steps 2 and 3 twice (total of three cycles).
5. Start the engine.

 

Thanks for the reply! I've tried taking off the negative cable and tried the 5sec on/off thing it worked until now. Everytime I open or lock doors with key it stays solid for like 20sec then off also wen It cranks it stays solid. How can I find out if its the IMMU or the ECM? I kno I can get my key reprogrammed but wat if this doesnt work? Wat other ways can I diagnose this? Is it possible my security system is just acting up? Do these parts normally go bad?

 

@DennisMik OP has P1612.

 

ooppps... brain fart. But in defense of myself, if you read the descriptions for codes P1610 through P1615, they are almost identical.

P1612 INFINITI - Chain of ECM-IMMU

Possible causes

Faulty or not programmed ignition key
Faulty IMMU
Faulty Engine Control Module (ECM)

Tech notes

This code is usually triggered when a not registered or damaged key is used to start the engine. When the starting operation is carried out five or more times consecutively with the same unregistered key, the system will lock.

If the problem occurs try disconnecting the car battery for about 30 minutes and then try starting the engine with a known registered key. If the problem persists you have to have the dealer erase the code and reprogram the keys again.

When is the code detected?

Communication impossible between ECM and IMMU (In rare cases, “CHAIN OF ECM-IMMU” might be stored during key registration procedure, even if the system is not malfunctioning.)

 

True. However, here's a summary of the codes and fixes:
P1610:LOCK MODE
(i)Unregistered ignition key is used; (ii) IMMU or ECM’s malfunctioning.
To escape from Lock Mode:
1. Turn ignition switch OFF.
2. Turn ignition switch ON with registered (spare) key. (Do not start engine.) Wait 5 seconds.
3. Return the key to OFF position. Wait 5 seconds.
4. Repeat steps 2 and 3 twice (total of three cycles).
5. Start the engine.

P1611:ID DISCORD, IMM-ECM
(i) System initialization is required; (ii) ECM

P1612:CHAIN OF ECM-IMMU
(i) IMMU; (ii) ECM

P1613:ECM INT CIRC-IMMU
IMMU circuit in ECM is bad

P1614:CHAIN OF IMMU-KEY
(i) Key is bad; (ii) IMMU

P1615:DIFFERENCE OF KEY
(i) Unregistered key is used; (ii) IMMU

Security indicator does not light up.
(i)Security indicator; (ii) Open circuit between Fuse and IMMU; (iii) Continuation of initialization mode; (iv)IMMU