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Torque » Torque OBD ECU Scanner » Torque Discussion / Ideas » Suggestions For Dashboard Widgets to Solve P0171 Code

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Author Topic: Suggestions For Dashboard Widgets to Solve P0171 Code
1nschultz
Member
Posts: 2
Post Suggestions For Dashboard Widgets to Solve P0171 Code
on: March 22, 2017 (GMT)

I have a 2001 Toyota Rav4 (178K Miles)

Unbelievable the amount of data and tools available in Torque Pro. I purchased this and loaded it up on my tablet with a good BT Reader.

Any thoughts on building a dashboard to help find the root cause of recurrent P0171 (Lean Bank 1) fault code?

So far I have cleaned my MAF, visually inspected for vacuum leaks, replaced air filter, cleaned PCV Valve, replaced both upstream O2 Sensors with OEM replacement parts. Still getting the same code and starting to run out of low hanging fruit.

thanks for the help. Amazing tool!

F-150Torqued
Member
Posts: 413
Post Re: Suggestions For Dashboard Widgets to Solve P0171 Code
on: March 22, 2017 (GMT)

By far the most common cause of lean code will be found to be a vacuum leak – which effects Fuel Trim(s) above a factory specified limit — That is exactly what produces the lean code. IMO, the best way to diagnose this is through “LIVE” monitoring Fuel trim (or trims if multi bank), while you use an “UNLIT” propane torch and blow it all around the engine vacuum lines, intake manifold, valve covers, Evap Solenoid, Oil Filler cap, bottom ‘o’rings on fuel injectors —- EVERYWHERE. If you hit a vacuum leak – the Short Term Fuel trims will go CRAZY as the ECU tries to compensate for the added combustible. A volatile spray (such as starting fluid, carb cleaner, or brake cleaner can also be used – but is more damaging to rubber components and more dangerous.

Another possible cause is an EXHAUST LEAK before the upstream O2 Sensor. (The clue for this is fuel trims should normally go way low to negative during “DECELERATION”). If cam retard or negative exhaust pressures allow fresh air to be sucked into exhaust, O2 Sensor will see it and ‘increase’ fuel trim(s) erroneously – leading to lean code.

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54371019

1nschultz
Member
Posts: 2
Post Re: Suggestions For Dashboard Widgets to Solve P0171 Code
on: March 22, 2017 (GMT)

good info.

So specifically in the Torque app, I should create a dashboard screen with the Fuel Trim Gauges, (LTFT1 and LTFT2 I think????) and perform the procedure as stated? I have a small handheld torch for copper pipe soldering I can use to inject some “combustible gas” into the area around a possible leak non lit… as opposed to a lit torch melting the hoses… lol

F-150Torqued
Member
Posts: 413
Post Re: Suggestions For Dashboard Widgets to Solve P0171 Code
on: March 23, 2017 (GMT)

Yes Sir. That’s exactly what I did. The upstream O2 sensors (O21S1 and O22S1 for V configuration engines) is useful to watch. It will go crazy too when a combustible gas hits a leak (or into the intake for a good test). And you are very perceptive – the lit torch would be bad for LOTS of things. Lol.

Attached is an example of what I use. I like the needle gauges for Fuel trims. Graphs work much better for rapid changing data like the normal ‘switching’ of O2 sensors.

Good Luck

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54371019

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