DIY: Replace dreaded steering-lock on 2009s and early 2010s.

Montez

Looks like 09/10 Max's are having that problem as well.

Will not start - Maxima Forums

kenchan

based on info at courtesyparts the 09+ maxima's are using a slightly different lock... but might be the same issue.

Product SKU: 48700-A35001

Ours is: 48700-JF00A (revB, C, D)

wstar

I haven't been able to find this in the Service Manual (censored so as not to aid theft?), but what would happen if you just removed the whole thing from the steering column and never re-installed it? Just never locks up? Not a huge issue IMHO. Would the car throw a code with it unplugged? I wonder if it's one UpRev can silence.

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kenchan

if you removed this unit car probably wont start cause the ECU will not receive the 'all clear' signal from the BCM. BUT i think if one can make a relay simulating this switch like how the vette folks did it on their car, it can probably work.

Montez

Yeah different part, same issue.....

fritz

Mine was intermittent (a bit like a manual lock needing a shake and seemed normal enough) but then expired...... and is on hold for possible warranty, if winter wheels and tires do not void it. Tricky Niss.

"Must be manufactured" in 2010 was my written deal on the car itself. The type B steering lock was made in early 2009 and the gas pedal assy made in late 2008.
Is that normal on a 2010 build car?

What happened to Just-in-time (JIT) production methods...I wonder.

Apart from un- reliability---4+ times now--the car's great. A curate's egg.

Any folk with an old lock? I'd like to disect it and try a relay to fool the CPU/BCM into thinking the lock is there. A real ignition switch and starter button could be nice too.


How are steering lock messages sent to the electronics to allow the engine to start ?

Fritz

wstar

EDIT: Scratch that idea, there's no easy way to fake it with a relay. Most of it is trivially fake-able since it's just "apply voltage to energize" and 2x redundant inverted feedback status switches that inform BCM + IPDM E/R whether the lock is in the commanded state, but then there's one critical bit that wouldn't work out: the BCM feedback on pin 111, which actually expects some timed pulses and state changes from some controller inside the lock unit in response to lock/unlock commands. So you'd need something a little more complex to fake it, like a cheap little microcontroller.

Even if you replaced the lock unit with a microcontroller-based fake: if you ever turned the steering wheel while the BCM thought it was locked, I wouldn't be surprised if it a threw a code because the steering angle changed when it shouldn't be possible.

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KaienZ34

^^Cool info i hope it works.

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ChrisSlicks

Maybe a 555 timer chip in combination. Although with the price of cheap integrated micro-controllers these days I would probably be tempted to go that route too.

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kenchan

ok sorry guys, you are like talking chinese to me now... no idea wat you're saying.

ChrisSlicks

可能在组合的一块555个定时器芯片。 虽然便宜的联合微型控制器的价格我大概那些日子会被诱惑连同路线也是

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wstar

Hmm I still think I don't quite understand it. I blame Nissan's documentation This is my best current guess at how the whole thing operates, now:

The lock unit supposedly has 7 pins on it. I'm giving them my own names for now since I still haven't found a pinout for connector M40, which is the actual connector at the lock unit:

G1: Grounded permanently
G2: Grounded permanently
P1: power supply, switched by IPDM E/R
P2: power supply, switched by BCM
S1: feedback switch output: +12V when locked, 0V when unlocked
S2: feedback switch output: 0V when locked, +12V when unlocked
C: communication line between lock module and BCM

Physical states:
The steering lock can be in one of two physical states: locked or unlocked. Once it has switched to a given state, it will remain in that state until commanded to change, regardless of whether any power is supplied to the unit. No relay has to remain energized to maintain one of the states or anything like that.

Power supply states:
P1 (IPDM E/R): When ignition is ACC or ON, no voltage supplied. Temporarily supplies battery voltage for a short while after opening the driver's door when ignition is OFF, or after pushing the ignition button once when it's LOCKed.
P2 (BCM): When ignition is OFF or ACC, +12V is supplied. When ignition is ON, it is not.
None of this completely makes sense, but the bottom line is, when the ignition is ON, neither power supply pin gets voltage, so no change to steering lock status can occur. When ignition is not ON, one of the two power pins (or both) will give it power at the right times for it to respond to a lock or unlock command, somehow.
It could be the case that P1 (IPDM E/R) only powers the feedback switches that drive S1 and S2, and P2 (BCM) powers everything else (the mini-controller that communicates with the BCM and actually moves the lock)

Switch states:
The S1 and S2 outputs are redundant inverted status outputs. They're almost certainly driven by physical switches that are tripped by the locking mechanism itself. In the unlocked state only one of them provides +12V, and in the locked state only the other does. If they're both +12V or both not +12V, that triggers a diagnostic failure. If they don't feedback that commands were followed correctly, that also triggers a diagnostic failure. Also of note: these are connected to both the IPDM E/R and the BCM, so for some reason both modules want to see this status.

BCM Communication Line:

This is the perplexing 7th pin "C":


It's listed as both an input and an output for the BCM. It seems definitely sure that the BCM is who sends that little pulse train against a 12V background to send LOCK and UNLOCK commands, as an output. I misunderstood earlier that the pulse train came from the lock module.

What really makes no sense is how any of this could be an input back to the BCM. Maybe it's mislabeled (from my point of view), and it's a BCM-output only, and the BCM drives it at +12V while LOCKED, and 0V when unlocked for 15+ seconds, and whenever it wants to send a command, it applies the +12V (if unlocked before) and then sends the pulse signal.

I guess someone would have to figure out what the manual means by clipping onto this with a scope (or really, even a multi-meter would do, since the only complex bit is already documented in the diagram above).

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ChrisSlicks

I think I agree from reading it that the pulse appears to be coming from the BCM. Not sure that you would capture the pulses with a multimeter, they appear to be only 1ms in duration at about 75ms, 35ms, 12ms apart respectively, definitely the job for a scope.

I think the main thing it going to be giving the ECU the correct signals on 97 (S1), 98 (S2).

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wstar

Well what I mean is, we don't really have to capture them, since they're documented and they have to come from the BCM because there's no other way it's signaling the module to make the change.

What I don't understand is whether the lock module also supplies voltage to this wire at times to provide feedback to the BCM or something.

One way or another, a replacement would need: a cheap microcontroller to sense the command pulses on the communication line and update a little NVRAM state indicating whether the fake lock is currently stuck-on or stuck-off, the microcontroller would need to be powered on any time either of the power supply pins lights up and provide S1/S2 feedback based on NVRAM, and possibly voltage feedback on the communication line as well.

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wstar

Of course, for a race car you could probably remove this module completely and it would be ignored as part of disabling all anti-theft code via UpRev. Mostly I'm just thinking about whether we could make a cheap small replacement to avoid $500 when an A/B-series unit fails, or to swap in preemptively and avoid failure.

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