Can someone tell me what wires to hook up from the PNDL switch to make the ECU think it is in drive? ECU and harness out of a 2007 truck. I don’t have the actual PNDL switch. Thx.

 

If you mean the switch that mounts on the side of the tranny, you don't usually need it for a conversion. It's just for neutral safety and send a signal to the dash for gear indicators. The ecu will know what is going on when it senses vehicle is moving, through the VSS signal.

 

I u have tuning software u can disable the PNDL switch in the pcm. Also if u are swapping over to a manual trans I would do a segment swap for the manual trans to work as it should.
If u need help with this or tuning PM me.

 

When I did my LS4/F40 manual transmission swap about 4 years ago, there was no manual transmission LS4 application (still isn't), segment swaps on the E67 were not that common, and I wanted to try and keep DoD with the manual transmission. So I wired everything up using the stock T42 transmission controller and the car still thinks it has an auto.

The diagram below is from a 2007 Impala SS (E67 T42 and a 4T65e-hd), so it might not be the same as your 2007 truck. But you should be able to find the same thing for the truck.

The Range switch has 4 wires that will either be open (not connect to anything) or connected to ground. For the Impala application Range Signals A & P are opne, and Range Signals B & C are grounded when the transmission range switch is in Drive.


When you wire it up this way, there are a few more issues to address.

If the ECM/BCM controls the starter curcuit, it won't start in D due to the safety interlock. My swap was in an 88 Fiero, so I just used the Fiero starter circuit and left the ecm out of the starting function entirely. The ecm would then set a code that the engine was starting in D, but that was easy to turn off with HP Tuners.

However, HP Tuners had very little access to turn off transmission codes with the LS4 (FWD) application, so I worked to mimic several signals to avoid setting codes I could not eliminate.

• Shift Solenoids and TCC. Wired up resistors (1K ohm I think) to all the shift solenoids and TCC so they would see a load and not set a code as well.
• Transmission temp, looked up the resistor values and added a resistor to show 180 degrees.
• The manual transmission VSS was wired up to the T42 just like the auto one.

The only code I couldn't eliminate (or turn off with HP Tuners) was the input shaft speed sensor (not connected, not replicated) code. A a guy with tunercat software was able to disable that code.

Once you get the engine running and the transmission not setting codes, then you need to adjust your airflow and spark tables to avoid stalling when you press the clutch (auto calibrations don't use a clutch pedal switch) or coast to a stop with the clutch pedal pressed.

As you can see there is a fair amount of work to run a manual with an auto calibration. If your application allows segment swaps and you can get the ecm setup for a manual transmission, I would go that route.

 

Thanks, I'll check this out. I have a 2007 4.8 LY2 swapped to manual in a fox body and I'm getting the dreaded 4000 rpm limiter. My tuner hasn't been able to figure it out. I threw the TCM back in trying to fool the E38 but no luck yet.

 

I'm doing the same engine ('07 4.8) into a BMW with a t56 and I'm getting the 4000 rpm rev limiter too. Super annoying.

Unfortunately I threw a belt, overheated the engine, and blew a head gasket, so tuning is put on hold while I fix the head gaskets

 

Fieroguru, is your ECU still running the full auto program or do you have it set to manual transmission but hooked up the TCM to make it work correctly?

 

It is still running the full auto calibration.
When I scan the car you can watch the transmission go through the motions of 1st, 2nd, 3rd and 4th gear (auto) while I am rowing the gears 1-6 with the manual.

 

No ****? That’s cool. Thanks for the advice, going to try some of your tricks.

 

Could it have the 4k rpm limiter bc it thinks its still in park? Under the engine fuel tab u can move the limiter to around 6k. See if this helps.

 

That seems to be the issue. We've already changed every limiter we could access. Doing some research the issue seems to be the E38 wants to see the TCM functioning. If it doesn't there is a limiter or torque management that shuts things down and we can't seem to access it. There's the reflash with a manual OS option potentially but that comes with a new set of issues. Not a big deal to wire up some resistors and see if that fixes things.

 

You might find this helpful. This is how I wired up the T42 TCM to fool it.

 

Awesome. Thanks.

 

Update: Thanks again to Fieroguru. Grounded C &D on the range selector and added a resistor for the trans temp sensor and the 4K limiter is gone. Wheelspin all the way through second gear.

Have a CEL on but it doesn’t seem to be affecting anything, going to finish hooking up the resistors per the chart and have my guy look at the tune again once I get everything cleaned up.

 

Glad to hear it worked for you!

When you take it back to your tuner, you might want to go ahead and disable every auto transmission code and diagnostic check as well as all torque limitations. Once all the transmission codes are turned off, you probably don't need any of the resistors for the shift solenoids or TCC.

The only non-transmission related code should be starting in D vs. P/N, but it is easy to turn off as well.

I did some testing with some relays on the range switches to make the ecm see P/N when the clutch pedal was pressed as well as when the shifter was placed in reverse, but the ecm didn't like it and disabled gas pedal function. After that I didn't explore any other options and just turned off the starting code.

 

Good to hear, what resistors and where did you add. Looks like I may have to add the TCM back in.

I wired up the "brake switch" to a power source today, thinking that might been the problem (without it, the ECM would think the brakes are always on). But, no change

 

Connecting the 4 range switch wires to show D (some ground some are left open) should take care of the Rev limit issue. The resistors are to keep most of the transmission codes from being set.

The details are included in the speadsheet I attached a few posts ago.

 

Like fieroguru said grounding the correct wires for the range selector seems to be what took care of the rev limit problem. The only resistor I hooked up was a 300 ohm resistor across the trans temp sensor wires.

 

So playing around tonight, I disabled all 3 rev limit types (spark, fuel, and throttle) and then went out for a test drive. Initially, I headed out and 4000 rpms I drove to town (5 miles) and on the way back I gave it some more gas and no 4000 rpm wall!

I stopped along the way and did a 1-2 pull up to about 5600 rpms (runs pretty good ) red pointer is max

So, I wonder if there is some hardwired rpm limit based on coolant temperature too

 

Nevermind.....was messing around again, and it cut out at 4000 again. I don't know why id let me go above 4000 a few times, and then the next time it didn't....weird