NEED HELP

[UPDATE: At day 2: With engine in idle, RPMs will not exceed 1,200 or so and even that is sluggish]
[UPDATE 2: At day 3: Engine started fine and the idle was at 1,500. Gas pedal is responding and reverse was back. Managed to back up the hill. Forward and reverse works, but service engine soon and MIL is still on and P2101 still shows. There is a second code, but it does not show (shows PENDING).]

Maxima 2010. Service Engine Soon light on and VDC off light on after battery change. Gears do not engage, although gear stick moves fine and gear indication is on dash. Car starts and runs fine.

Engine code is P2101, i.e. Throttle Actuator “A” Control Motor Circuit Range/Performance. It is usually triggered when vehicle’s powertrain control module (PCM) detects that the actual throttle position does not match the desired throttle position. Once this happens, your PCM may put engine in “limp home mode” to prevent unwanted acceleration.

Nissan says:

• Electric throttle control actuator does not function properly due to the return spring malfunction.
• Throttle valve opening angle in fail-safe mode is not in specified range.
• ECM detect the throttle valve is stuck open.

1. Never actually been in limp mode on my Maxima. Will Nissan allow reverse in limp mode or is it not possible? (again, for clarity, the shift into reverse is shift and the R is showing on dash).
2. Found this pointed to on another thread (https://www.obd-codes.com/p2101). Seems like a match. Opinion?
3. Help?

P.S. I am, of course, on a hill, so the car just rolls downhill until I hit something.

 

Looks like broken CVT belt

 

I got none of the symptoms (leakage, sound, etc.). How do you figure?

 

I've seen Max with broken cvt belt - no annoing sounds and it was the same as in your case.

 

I just reread ypur initial poat and started scratching my head. Did all this occur AFTER replacing the battery? Or did I misinderstand?

 

You understood that correctly. The car was not used for a couple of months and I replaced the battery (which was (of course) flat and also (somewhat) expired at +3 year). The car started fine (and, yes, everything is tight), but does not engage in reverse and the MIL is on (and P2101 is thrown).

I don't know if it will engage in drive (I have zero space left on the hill to roll forward). <== See update above.

 

Lets run a few tests. You will need a voltmeter for this test. Make sure the car is running for these tests so be careful.
1.) Lets put the scale down to 20v and with your positive lead on battery negative, take the negative lead and touch it to a few places on the engine, cvt, and body. You should not have a reading more than .25vdc on any ground point.
2.) do the same test from battery positive to alternator. Once more, should be close to 0.
any more voltage means you have bad connections/cables somewhere.

if both of these tests are good, lets disconnect the battery. Connect a small load across the battery positive cable and battery negative cable. This will discharge any residual voltage from components and help ensure pcm goes to a default config. Leave this this in this mode for a few hours. It may be a good time to put a battery charger on the battery to ensure full charge later


Reconnect the battery and clear your codes with a scan tool before starting.

Start your car and lets see if throttle response is back. If not, lets check the charging ckt. Make sure you are charging around 13.8vdc. 14.8 or higher or 12.5 and lower may mean a bad alternator which will indeed cause issues with throttle response and going into gear.

Report back on any codes (pending or otherwise)

This should help clear some of the probs others have had (bad alternator or alternator with a lot of ac components on it will cause your symptoms as well)

Of course that relay you mention could be toast too but i believe these relatively easy checks should help give us direction.

 

Thanks... You may have missed my update above.

1.The car is now able to drive and throttle control seem to be back and normal. Idle is about 1,500 at cold. Reverse and Drive works. Feels and sounds normal.
2. MIL is still on. Service Engine Soon light is still on. P2101 is still on. VDC light is off (so I think we are out of limp mode). There is two codes indicated on the ODB, but only P2101 shows and is marked Pending.
3. I have not run it anywhere. Just backed it up and moved it forward to get it out of the hill. I am a little apprehensive to run the car.
4. I can do the steps that you laid out, but does it make sense? (I am not sure what you mean when you refer to a relay in the last line... I a did not refer to a relay in my post)
5. Should I simply reset the codes using the ODB 2 and cycle and let it idle to see what happens? If so, is there a way to reset Service Engine Soon?

 

You are correct, i should have used more proper verbiage for the actuator vs relay. Mom was an English major and is probably spinning in her grave but, in my (admittedly poor) defense, I was responding on my phone . Apologies.

Re should you still run the tests...I dont know that you have found the "systemic cause" which, given the adjacency to the battery replacement, still leads me to believe you may have a voltage stability issue...wither from bad connections, oxidation, cabling, or even cbarging components should still be checked IMHO.

RE Service Engine Soon, or MIL, indicator extinguishing; Yes, clearing the codes should make the light go out as long as the codes dont come back!

Give it a shot and let us know! Also, You will need to eventually take the car for a spin (Some may suggest extended idling but I am not a fan of that) to validate all is good in tbe world!

 

I will clear the codes, measure the voltages, and - eventually, when my courage exceeds zero - take the Max for a spin around the block.

I will report back.

Thanks.

 

Cleared code and MIL light did indeed clear as well. Idled for a while (still haven't driven the Max). Code has not reappeared.

Battery voltage is 12.25 or so, when Maxi is idling it goes to 14.25 and then falls (gradually) to 13.0X where it stabilized, so within the range that you proposed, but not 13.8. Is this a problem?

 

No, this sounds reasonable for a fully charged batrery and allowing for your meter. Did you do the voltage drop tests?

 

I did NOT perform the voltage drop test (I got very excited). I will do so and get back to you.

I took the Max around the block and had zero problems, so there is that.

 

The voltage drop on misc. points yielded only negligible (near zero) drops. Anything else I can do here?

P.S. Also, the battery leads did not get hot, so I do not suspect the battery leads.

 

As your test drives are good, lets chalk this up to bad voltages from the battery and siting for so long. Keep an eye open for alternator voltage anomalies as high voltage and/or AC components can cause all sorts of issues.

I assume the error has NOT recurred, so please correct me if it has. If Not continue to enjoy your ride


Lt

 

Thanks, LT. I guess we will see

 

Thanks, LT. I guess we will see.