P1136

P1136 on VW/Audi is Fuel Trim Additive (Long-Term Lean Bank 1) System Too Lean — the ECM's additive long-term fuel trim (the slow-learn correction stored in EEPROM) has drifted past the lean threshold, typically +15% or higher sustained over multiple drive cycles. This is the deep-cause version of a P0171: short-term trims have been compensating long enough that the ECM has written the correction permanently into the additive table. Cheapest-first ladder: scan live data with VCDS or any OBD tool that displays both additive (FRA / long-term) and multiplicative (FRM / short-term) trims separately — if additive is +15% or higher at idle and multiplicative is also positive under load, you have a real lean condition, not a sensor calibration drift. Smoke-test the intake side at 10-15 inHg: look for smoke escaping the PCV crankcase breather hose (PCV diaphragm tear is the #1 EA888 cause), the intake manifold gaskets, the brake booster hose, or the fuel tank-vent shutoff valve stuck open. Inspect the MAF sensor element for dirt and re-test trims after cleaning with MAF-safe cleaner. Pull the upstream O2 sensor and check the tip for white ash (coolant entering combustion = head gasket) or fuel-wet black (running rich, contradicts the lean code = wiring fault). Don't replace the O2 sensor on a P1136 until you've smoke-tested the intake and verified fuel pressure under load — the O2 is usually telling the truth and the leak is real.

Vehicle-specific patterns: 2008-2014 VW/Audi 2.0 TSI/TFSI EA888 (Jetta GLI, GTI, A4, A5, Q5, Passat) is the dominant P1136 platform — the failure is almost always the PCV diaphragm on the valve cover tearing internally, creating a massive vacuum leak that pulls the cover into the intake. The fix is a complete valve cover/PCV assembly, not just a gasket. Same engines also throw P1136 from carbon-fouled intake valves (direct injection only, no port-injection wash) restricting airflow asymmetrically — walnut blasting resolves it. 2004-2010 1.8T 20-valve (B6/B7 A4, Mk4 Jetta/GTI) throws P1136 from PCV breather valve failure and from the well-known cam-chain tensioner gasket leak introducing unmetered air. 2009-2015 2.0 TDI EA189 (Jetta TDI, Golf TDI, A3 TDI) throws P1136 less often (diesel runs differently) but can set it after DPF/EGR-related issues introduce air on the intake side. Estimated repair: $400 (PCV valve cover DIY on an EA888) to $1,800 (cover + walnut blast + smoke test at a shop).