How is fault code P0068 fixed?

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Plug in a scanner, log P0068 and any friends sitting alongside it like P0100 to P0105, then clear and road-test to confirm it's a live fault and not a one-off 2. With the engine running, go round every boost pipe, clamp and vacuum hose looking and listening for a leak. On a turbo a popped intercooler pipe is the usual culprit and you'll often hear it under load 3. Pull the air filter and check it isn't choked, and have a look at the MAF element for oil or muck, clean it with proper MAF cleaner if it's grubby 4. Check the wiring and plugs at the MAP, MAF and throttle sensors for green corrosion, chafing or a loose pin 5. Watch live data and compare throttle position against MAP and MAF as you gently blip the throttle. Healthy and they track together. If one lags or sits stuck while the other moves, you've found your bad sensor 6. If the intake's tight and the sensors track properly, look at the throttle body itself for carbon build-up holding the plate off its true closed position, clean

MAP / MAF - Throttle Position Correlation

Jump to the fix

Severity

Medium

Can I keep driving?

Usually drivable, but get it diagnosed without delay.

First step

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Plug in a scanner, log P0068 and any friends sitting alongside it like P0100 to P0105, then clear and road-test to confirm it's a live fault and not a one-off 2. With the engine running, go round every boost pipe, clamp and vacuum hose looking and listening for a leak.

PPowertrain
0Generic code
0Fuel / Air
68Sequence number

What does it mean?

P0068 means that the Powertrain Control Module (PCM) has detected an excessive degree of variation in the input voltage signal from the throttle position sensor (TPS) as compared with voltage input signals from the mass air flow (MAF) sensor and the manifold air pressure (MAP) sensor. The PCM reads and calculates these individual engine drivability sensor signals and then compares them to help develop fuel delivery and ignition timing strategy.

The PCM also utilizes this information to ensure that the fuel-to-air ratio remains constant, controllable, and within acceptable limitations. If the detected voltage values of these three sensors (triangulated) fail to coincide with programmed desired parameters, over a specific period of time or engine revolutions, a diagnostic trouble code will be stored and a malfunction indicator lamp will likely be illuminated.

Symptoms

Likely causes

How to fix it

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This information follows the generic OBD-II definition and does not replace a vehicle-specific diagnosis. The severity rating is rule-based; an authorised diagnostic reading is required for a definitive answer.