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sean, Technician
Category: Mazda
Satisfied Customers: 3105
Experience:  Technician for 30 years.
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I have a mazda 323 2l sport 52 plate , my engine management

Customer Question

I have a mazda 323 2l sport 52 plate , my engine management is on and when i have had it checked out it came up with the codes P0032power train, poo38powertrain, po421 warm up cylinder the man who did the diagnostic said they all relate to one item - which is a lamby sensor - but he didnt know which one as it has two , and the local shop which sells them also said they need to know which one - can you help at all
Submitted: 3 years ago.
Category: Mazda
Expert:  sean replied 3 years ago.

Hello, I hope the following assists you.

The codes P0032 and P0038 refer to both lambda (HEGO, oxygen) sensors, the codes relate to both heater circuits for the sensors so it's unlikely that both sensors have failed and is more likely to be a power or earth failure to the sensors. Check that there is 12 volts to the heater on each sensor and that there is an earth at each sensor, the earth is controlled by the engine management so it's unlikely to be this as each sensor is earthed at different pins on the engine management where as the 12 volt supply is from the same source.

The P0421 catalyst warm up code is probably due to the heater circuit not operating correctly on the sensor after the catalyst so start with checking this sensor heater operation.

Let me know if I can advise further and I'll reply as soon as I'm able to.

Best wishes,