OBD-II Code
P1155
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$40–$620
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P1155 is the Bank 2 mirror of P1135 and indicates a heater circuit fault on the upstream AFR sensor for Bank 2 Sensor 1, which on transverse Toyota V6 engines is the rear (firewall-side) sensor and on longitudinal V6 or V8 platforms is the passenger side.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP1155 is the Bank 2 mirror of P1135 and indicates a heater circuit fault on the upstream AFR sensor for Bank 2 Sensor 1, which on transverse Toyota V…
P1155 is the Bank 2 mirror of P1135 and indicates a heater circuit fault on the upstream AFR sensor for Bank 2 Sensor 1, which on transverse Toyota V6 engines is the rear (firewall-side) sensor and on longitudinal V6 or V8 platforms is the passenger side.
The diagnostic ladder is identical to P1135 but with one critical Bank 2 wrinkle
- on 2GR-FE and 3MZ-FE engines, Bank 2 Sensor 1 sits directly behind the engine against the firewall and is bathed in radiated exhaust heat from the rear manifold, which is why it statistically fails years before Bank 1.
- Begin by reading live AFR heater current in Mode 06 or via Techstream (specification is 0.2 to 2.0 A, with most healthy sensors landing near 1.0 A at steady state); a flat 0.0 A reading points to an open circuit, while a pegged-high reading points to a shorted heater element.
- Verify the heater fuse and relay before condemning the sensor.
- The costly mistake here is pulling the intake manifold to reach Bank 2 only to discover the fault was a chafed wire at the bracket, or replacing the sensor with a cheap universal four-wire unit that lacks the calibration resistor Toyota's PCM expects.
Vehicle-specific patternsToyota 2GR-FE 3.5L V6 (Camry, Avalon, Sienna, Venza, Highlander 2007-2014) is the dominant P1155 platform; the rear Bank 2 sensor typically fails at…
Toyota 2GR-FE 3.5L V6 (Camry, Avalon, Sienna, Venza, Highlander 2007-2014) is the dominant P1155 platform; the rear Bank 2 sensor typically fails at 80k to 120k miles, and the upper intake plenum must be removed for access, which is why labor dominates the bill. Toyota 3MZ-FE 3.3L V6 (Sienna, Highlander, Camry, Lexus RX330 2004-2007) shows the same rear-bank early-failure pattern; Denso 234-9009 is the correct OE part for many of these. Toyota 1GR-FE 4.0L V6 (Tacoma, 4Runner, FJ Cruiser 2005-2015) sees P1155 more often from harness chafe at the rear bank than from sensor death. Toyota 2UZ-FE 4.7L V8 (Tundra, Sequoia, Land Cruiser 2000-2009) sets P1155 most commonly from a failed EFI main relay or corroded ground at the rear head.
Estimated repair$40 to $620.
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