Accelerator pedal position sensor - P2121 (1 Viewer)

[gfmcl]

On the home stretch of a 2400 mile trip, about 300 miles from home, check engine light comes on. Loss of acceleration, pulled over. Fortunately, had a OBD scanner, and the code was P2121 - APPS sensor. I was able to clear the code and made it home without further issue. Dodged a bullet.

So, now what to do. Since the code is cleared, wait to see if it happens again, or have it checked with tech stream ? Would tech stream even show anything since the code is cleared ?

-g

 

[ipxih12]

glad you made it home! should be ok to keep driving. see if it triggers again.

 

[CorporalClegg]

If the code didn't return you have an intermittent problem. TIS does have a check mode function, this will change the code set criteria to set the DTC at first failure under a reduced amount of time. I don't know the extract criteria for a 2121 but it's a pretty simple fault to diagnose. what year is your cruiser? You'll basically compare your APP voltages against the TPS, you'll want to watch for the signal for a smooth voltage transition from closed throttle to WOT. there will be a PID in TIS you can watch before breaking out other tools.

 

[gfmcl]

If the code didn't return you have an intermittent problem. TIS does have a check mode function, this will change the code set criteria to set the DTC at first failure under a reduced amount of time. I don't know the extract criteria for a 2121 but it's a pretty simple fault to diagnose. what year is your cruiser? You'll basically compare your APP voltages against the TPS, you'll want to watch for the signal for a smooth voltage transition from closed throttle to WOT. there will be a PID in TIS you can watch before breaking out other tools.

It's a 2006 LX470. I'm no techstream expert, but I'll be taking it for some other, unrelated service, so I'll pass this information along.