My ED Sprint is using too much juice (18-20l/100km around town) so I've run a KOEO test and it gives codes

34 (all tests EVP voltage above closed limit)

41 Right HEGO circuit faulty

91 left HEGO circuit faulty

It's recently had both O2 sensors replaced (due to the same codes).

Question is, when running a KOEO test, are those codes generated during the test, or is it accessing previously stored codes (that haven't been deleted)?

If the 02 sensors have been charged you should just be able to clear codes and they shouldn't come up again.

thanks yeah as it's still using too much fuel I'm wondering if it could be the wiring/connections that are causing the fault

If the codes come back after being cleared then I'd agree could be a wiring issue.