Back story.
2008 Xterra Offroad. 145,000 miles.

Went to start vehicle. No response, no tick, no crank, no data link, but a strong battery. Also the most reliable vehicle, regular maintenance, So this was a shock..
Replaced crank and cam shaft sensors (shot at the cheap fix). Didn't work.
Fast forward to swap ECM, reprogram ECM to VIN, and keys reprogrammed. And she started and data link was back. Reading live data, the throttle voltage was not corresponding to normal values, while pedal depressed. EVERYTHING ELSE READING NORMAL. Very minimal throttle response.
Changed Throttle Body, and Mass Air Flow sensor.
Now I am stuck with permanent codes P0102, P0123, P0223, P2119, and the car is stuck in fail safe mode. Throttle opens as it should, engine revs in park, put it in gear with rear tires off the ground to run through the gears, we be speeding through the garage and she is shifting and purring as sweet as can be.
Put the tires on the ground, put her in gear, at best, she goes 3-4 mph with the pedal floored, for just a few feet. Put her in 4 low, she goes about 10 mph. Just enough to get the vdc light off.
From testing connectors, harnesses, continuity to the ECM, every way of testing a part or harness, as per FSM.
Any help would be appreciated

P0102 is a flatlined MAF sensor, that will make it limpy all by itself. P0123 is TP #2, P0223 is TP #1, and P2119 is derivative because the ECM has no clue where the throttle plate is. The MAF problem can't possibly be related, because it runs off 12V from the ECM Relay and the TP's run off 5V from the ECM, and they don't share grounds. It sounds to me like you have some wiring issues or connectors that aren't connected, so start by checking power and ground voltages at those sensors and make sure all the relevant connectors are seated and don't have bent pins, especially the ECM.

You'll find your wiring diagram starting on EC-443 here:
https://www.nicoclub.com/service-manual ... 8%2Fec.pdf

VStar650CL wrote: ↑

Thu Jul 14, 2022 7:14 pm

P0102 is a flatlined MAF sensor, that will make it limpy all by itself. P0123 is TP #2, P0223 is TP #1, and P2119 is derivative because the ECM has no clue where the throttle plate is. The MAF problem can't possibly be related, because it runs off 12V from the ECM Relay and the TP's run off 5V from the ECM, and they don't share grounds. It sounds to me like you have some wiring issues or connectors that aren't connected, so start by checking power and ground voltages at those sensors and make sure all the relevant connectors are seated and don't have bent pins, especially the ECM.

We have checked everything. No bent pins, grounds are good, we used FSM for all diagnostic and testing. Everything is metering according to specs listed in FSM. The only testing we can't run is when it specifies to get RPMs higher than we can actually get .
Literally at a loss. According to FSM fail safe for the codes is to limit rmps via fuel cut, but we can't even get one drive cycle, let alone 3 to even try to get the codes to clear themselves

P-DTC's won't cause anything to limit, only current ones and some "past" ones. Limited throttle opening is a failsafe characteristic of all those TP codes. So either something is screwed with your scanner that it's showing DTC's as permanent when they're actually current, or something is screwed with your new ECM.