Rear O2 on bank 2 slow — often a warning before P0430.
P0159 — also written PO159, P 0159, 0159 — is the OBD-II code for o2 sensor circuit slow response (bank 2, sensor 2). Same code, same fix: this page covers every spelling of it.
This is your post-cat sensor on Bank 2 (the side without cylinder number one) taking too long to switch its voltage. It’s a common 'old age' code on V6 Petrol Vauxhalls and JLR engines.
P0159 is a emissions fault code, typically costing £90–£320 to put right in a UK garage.
What P0159 actually feels like to drive
- The EML (Engine Management Light) stays on, usually appearing after a long motorway run.
- Passed the MOT emissions test but the light came back on two days later.
- A slight drop in MPG, though nothing catastrophic.
- Slightly 'tappety' or huffy sound from the exhaust manifold area when cold.
- Engine feels perfectly normal to drive—no stuttering or loss of power.
What causes P0159?
- Aged sensor
- Cat starting to fail
UK vehicles that throw P0159 most often
- Jaguar XF 3.0 V6 Petrol (2008-2015)
- Vauxhall Insignia 2.8 V6 Turbo (A28NER)
- Range Rover Sport 4.2/4.4 V8 Supercharged (2005-2009)
- Toyota Land Cruiser 4.0 V6 (1GR-FE)
- Ford Mondeo ST220 3.0 V6
- Lexus RX350 3.5 V6 (2GR-FE)
How P0159 is fixed
- Replace sensor
- Retest with fresh sensor before cat
The P0159 misdiagnosis that wastes money
I see folks throwing cheap universal O2 sensors at this all the time, thinking they've saved a packet. On a V6 Jag or an old Range Rover, those 'one-size-fits-all' sensors are rubbish—the heater circuit resistance is never quite right, and the code pops back within 50 miles. Most of the time, P0159 is the sensor literally 'getting tired' as it hits 80k miles, but don't ignore the possibility that the cat is starting to crumble and isn't holding enough oxygen to keep the sensor happy.
What a UK garage should charge for P0159
For a Bosch or Denso sensor (don't buy the unbranded eBay specials), you're looking at £110 to £160 just for the part. Labour is usually an hour—about £70 to £90 at a decent indie—unless the sensor is seized solid in the pipe, which they often are in the UK climate. If you go to a main dealer, expect a bill closer to £450 once they've added their 'diagnostic fee' and marked up the OEM boxed part.
P0159 repair cost in the UK
Most P0159 repairs land between £90–£320 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P0159
If you're taking this to a garage, ask them to 'graph the live data' for Bank 2 Sensor 2 during a road test. You want to see if the voltage is lazy or flatlining when you lift off the throttle. If they just want to swap the sensor without looking at the graph, be wary. Also, check for exhaust blows—even a tiny pinhole near the flange can let air in and trick the sensor into acting 'slow'. A proper smoke test on the exhaust saves you replacing a £150 sensor for a £2 gasket.
Can you drive with P0159?
Yes.
Urgency: low.