P0432 means the main catalytic converter on Bank 2 has dropped below the efficiency threshold the ECU expects. Bank 2 is the cylinder bank that does not contain cylinder 1, so P0432 only applies to V6, V8, V10, V12, or certain flat engine layouts. It is the Bank 2 equivalent of P0422.
DTC/P0432·Audi
P0432 on Audi: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Audi
P0432 on a Audi means the main catalytic converter on Bank 2 has dropped below the efficiency threshold the ECU expects. Bank 2 is the cylinder bank that does not contain cylinder 1, so P0432 only applies to V6, V8, V10, V12, or certain flat engine layouts. It is the Bank 2 equivalent of P0422.
Repair cost on Audi€163 - €2340
What does P0432 mean on a Audi?
Audi A6
2005-2024On the Audi A6 3.0 TFSI (EA837) and 3.0 TDI V6, P0432 typically appears at 180,000 km on the Bank 2 main cat. The Bank 2 main cat on the EA837 supercharged V6 is accessible from below without dropping the subframe, which keeps labour reasonable. On 3.0 TDI variants check for soot loading from a stuck EGR valve before condemning the cat itself.
What causes P0432 on a Audi?
Beyond the generic causes listed on the main P0432 page, these are the Audi-specific patterns we see most often:
Audi A6EA837 Bank 2 main cat aging around 180,000 km
Audi A6Stuck EGR valve on 3.0 TDI causing soot loading on Bank 2
How to diagnose P0432 on a Audi with OBD2
Follow these steps to pinpoint the root cause of P0432:
- Confirm the engine actually has Bank 2 (V6, V8, V10, V12, or flat layout). On inline engines P0432 indicates a wiring or scan-tool fault
- Read freeze frame data and check for companion codes (P0431, P0430, Bank 2 misfires, Bank 2 lean or rich)
- Inspect the full Bank 2 exhaust run for leaks, particularly at flange joints, slip-fit connectors, and flex pipe sections
- Graph the Bank 2 downstream O2 sensor at steady 2,000 to 2,500 RPM. A healthy main cat keeps it stable around 0.4 to 0.6 V
- Compare Bank 1 vs Bank 2 fuel trims. If Bank 2 long-term fuel trim is consistently 8 percent or more above Bank 1, the underlying mixture imbalance is degrading the Bank 2 cat
How much does P0432 cost to fix on a Audi? (EUR)
Estimated repair costs on a Audi (Audi parts and labour typically run 30% above the average for this code).
Prices estimated as of May 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0432 on Audi
These codes commonly cluster with P0432 on Audi vehicles:
FAQ: P0432 on Audi
What is the difference between P0430 and P0432?
Both are Bank 2 catalyst efficiency codes. P0430 is the generic OBD-II code used by most manufacturers. P0432 is used by some manufacturers (commonly Chrysler-Jeep and some European brands) to specifically label the main catalyst when the exhaust has a separate warm-up pre-cat and main cat per bank. The diagnostic approach is essentially identical.
Can I replace just the Bank 2 main cat and leave Bank 1 alone?
Yes, if Bank 1 shows no efficiency codes and the downstream O2 sensor traces look healthy. However, on engines past 180,000 km, the Bank 1 main cat is often within a year of triggering its own efficiency code, and many owners replace both at the same time to save on overlapping labour.
Why does only Bank 2 fail when both banks have the same mileage?
Asymmetric wear is common. Causes include intake manifold geometry that delivers a slightly different air-fuel ratio per bank, exhaust packaging that traps more heat on one side, or a single failing injector or coil that has been quietly causing partial misfires on Bank 2 for months.
Will an aftermarket Bank 2 main cat pass emissions?
Quality OEM-equivalent aftermarket cats from reputable European brands generally pass emissions and periodic technical inspection. Very cheap universal cats often do not meet the OEM oxygen storage spec and will trigger P0432 again within weeks. Always buy a cat with the correct certification (E-mark or equivalent for the EU market).
Looking for the full P0432 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0432 guideSkanyx · Audi
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