Questions and Answers

Nissan Altima Codes 11 And 21 Q. Vincent, I have a 1994 Nissan Altima GXE with the 2.4-liter DOHC four cylinder engine and a manual 5-speed transmission. The car has a little over 200,000 miles and has been running great until a couple of months ago. It first started with cutting off when slowing down. This really didn't happen often so I dismissed it as a fluke and kept going.

Then It started happening more frequently and I even started noticing the lights start to dim right before it died. I wrote this off saying that if the engine is cutting off then the alternator will not charge properly and the lights will dim. I also noticed that the fan blower would also work in conjunction with RPMs.

Next thing to happen was that the fan blower stopped working altogether. I manage to get by this by driving at higher speeds to keep my heat coming through the vents. I know about the blower resistor from reading your column, but I don't get anything on any blower setting (1-4).

Finally, I replaced the battery because I was told by the folks at the auto parts store that the battery was dead. This seemed to work for a little while and then the problem started again. Next I changed the plugs and plug wires. The plugs did not have a gap adjustment on them and are set to .043 inch. This did not work either and the car continued to stall.

Finally I think I hit the bottom with this problem and I was going down the road and the engine acted like it wasn't getting any power and the RPMs were going up and down until it finally stalled. Giving gas before the stall did not help and caused the car to shut off quicker. The car would eventual start but would idle really rough and eventually smooth out to normal RPMs.

At the present moment the car will not start and the Engine Codes are reading 11 (1 long and 1 short flash) and 21 (2 long and 1 short flash). I looked in my Haynes Repair Manual and they give the following information:

• Code 11 -- Camshaft Position Sensor
• Code 21 -- Ignition Signal

Does it sound like to you that this may be a problem with just the sensor which causes the coil to not receive the proper voltage? I really don't have the money to go to a repair shop and have them use the trial and error approach to fixing this by replacing parts until they get an idea about what is happening.

Should I just follow all the steps to test the ignition system or do you think I should just replace the distributor which includes the built-in camshaft position sensor? Just so you know I have already replaced a fuel pump and fuel filter, and at the moment I can hear the pump working when I turn the key to ON before starting.

Thanks,
Adam

A. The trial and error method of auto repair can get very expensive very quickly, even for a person who has more money then they know what to do with. And replacing everything does not guarantee you will fix the problem. Testing components is a lot cheaper and a lot quicker.

Here is the test procedure for the code 11, Camshaft Position Sensor.

Here is the test procedure for the code 21, Ignition signal..

These tests will check the wiring as well as the components. Keep in mind that if the engine is running as it should, these tests could be inconclusive. You need to test the components when the symptoms are present or they will check out as good.