2004 Maxima Limp Mode! Help!

[Hellrot318is]

Ok, so my girlfriends car, 2004 Maxima with 55K on it was working fine until last night. We parked it, went to the bar, came out, and it had a hard time starting. We were like WTF and then looked at the gas gauge and it was all the way at the bottom. "Someone jacked our gas" we thought because we put in $20 earlier in the day. Then we realized that the car was started, but no gauges were working. It appeared to be in limp mode, as mashing the gas barely made it move. We got it home, disconnected the ground cable, and reconnected it, hoping to reset the ECU to start fresh. No change, Same thing, except it will not start now. Just cranks and cranks.

The only lights that are on is the battery, ABS, and brake lights. Also, the security LED on the dash is on solid, and when you try and lock the doors with the remote, it locks, but the horn does not beep.

A mechanic friend said that the fuel pump is probably jacked, and put the car in safe mode. He also said for this car they are not cheap.

Anyone have any other ideas?

[loystock]

Crazy things do happen when the alternator is failing. And the battery could have been weakened due to faulty alternator as well as multiple start attempts. A good battery should read >12.5VDC. If voltage is less than 12VDC, it's technically dead and cannot start the car. See if you can jump start the car. Once the engine is running, the alternator charging voltage should be >13.8 VDC (spec is 14.1-14.7 VDC). Also check the fuses and relays.

You can check if the fuel pump is operational. The pump is located in the fuel tank and is accessible from the rear passenger seat. Turn Ignition Switch to ON and the Fuel Pump should run for 5 seconds (you should be able to hear it humming, if operational).

The Security System LED is controlled by the BCM (Body Control Module). If it detects a problem, it will disable the starter. Refer to the FSM (Factory Service Manual) and go to BL (Body, Lock and Security) and SC (Starting and Charging)chapters for more info.

http://www.nicoclub.com/FSM/maxima/2004/

Borrow/rent an OBD II scanner to see if you have trouble code(s) which can help in the fault isolation.

[Hellrot318is]

I scanned the codes and got code P0462. Fuel level sender low voltage. My mechanic friend says replace the fuel pump and fuel level sender. Sound right?

[loystock]

Replacing the fuel pump assembly is expensive, time consuming and involved a risk of fire. It may or may not fix the problem. So if I were you, I would explore and check other possible causes. The trouble code P0462 may be caused by bad harness/connector, unified meter and A/C amp or fuel level sensor.

From the link provided in my earlier posting, you can start with page EC-365 (Engine Control) to get a better understanding of your problem. Also go to DI(Driver Information) chapter as it gives you description and location (DI-7&8), wiring diagram (DI-11&12) and built-in diagnostic (starting on DI-15). Some steps may require a Nissan Consult but others are just basic testing.