P0135 on Kia vehicles
O2 Sensor Heater Circuit (Bank 1 Upstream) — what it means on a Kia, whether it's safe to drive, and the fixes by model and year.
P0135 on a Kia means o2 sensor heater circuit (bank 1 upstream). Most vehicles stay drivable short-term, but diagnose it promptly. The most common cause is failed o2 sensor heater element (open or shorted internally) (typically $150–$450). Pick your Kia model below for its known failure patterns, recalls, and TSBs.
What does P0135 mean on a Kia?
P0135 is set when the ECM detects that the heater element built into the Bank 1 upstream oxygen sensor is not drawing the expected current when commanded on. Zirconium O2 sensors only produce a usable signal above approximately 350 °C / 660 °F, so they include an internal heater that brings them to operating temperature quickly after cold start. P0135 means that heater is open, shorted, or being under-powered.
P0135 is a standardized OBD-II code, so its definition is the same on every Kia. What differs by model and engine is which cause is most likely — pick your Kia model below for a diagnosis tuned to its known failure patterns, recalls, and TSBs.
Is it safe to drive a Kia with P0135?
In most cases a Kia stays drivable for short trips with P0135 active, but diagnose and repair it promptly. This is a moderate-severity code — ignoring it can lead to further damage or a failed emissions test. Exact tolerance depends on the model and engine.
What causes P0135 on a Kia?
| Cause | Likelihood | Estimated repair (USD) |
|---|---|---|
| Failed O2 sensor heater element (open or shorted internally) | Most common | $150–$450 |
| Blown O2 heater fuse — Always check the fuse before condemning the sensor. | Common | $5–$30 |
| Damaged sensor wiring (chafed against exhaust) | Common | $80–$350 |
| Corroded O2 sensor connector | Common | $30–$200 |
| Failed O2 heater relay (on vehicles with one) | Occasional | $30–$150 |
| Failed PCM driver for the heater circuit (rare) | Rare | $400–$1,500 |
Repair costs are typical US ranges and vary by Kia model, model year, and labor rate. A diagnostic trouble code is a symptom, not a guaranteed failed part — confirm the root cause before replacing anything.
P0135 by Kia model
Select your Kia model and year for a P0135 diagnosis tuned to that vehicle's failure patterns, recalls, and TSBs.
Kia Sportage
819 NHTSA owner complaints · 10 recalls on record across the years covered below.
Kia Forte
607 NHTSA owner complaints · 8 recalls on record across the years covered below.
Kia Sorento
1,828 NHTSA owner complaints · 15 recalls on record across the years covered below.
Complaint and recall counts are NHTSA totals for the model years covered on this site, not counts specific to P0135.
P0135 on other makes
Other codes on Kia vehicles
P0135 on a Kia: frequently asked questions
What does diagnostic trouble code P0135 mean on a Kia?
P0135 is set when the ECM detects that the heater element built into the Bank 1 upstream oxygen sensor is not drawing the expected current when commanded on. Zirconium O2 sensors only produce a usable signal above approximately 350 °C / 660 °F, so they include an internal heater that brings them to operating temperature quickly after cold start. P0135 means that heater is open, shorted, or being under-powered. P0135 is a standardized OBD-II code, so the definition is the same on every Kia — which cause is most likely varies by model and engine.
What are the symptoms of P0135 on a Kia?
Check Engine Light is illuminated. Extended open-loop fuel-trim period after cold start (worse fuel economy until warm). Slow O2 sensor switching that may take several minutes to begin after cold start. Possible drivability symptoms if the engine remains in open loop too long. Vehicle may fail emissions / smog test
What causes P0135 on a Kia?
Failed O2 sensor heater element (open or shorted internally) (most-common). Blown O2 heater fuse (common). Damaged sensor wiring (chafed against exhaust) (common). Corroded O2 sensor connector (common). Failed O2 heater relay (on vehicles with one) (occasional). Failed PCM driver for the heater circuit (rare) (rare)
Is it safe to drive a Kia with P0135?
In most cases a Kia stays drivable for short trips with P0135 active, but it should be diagnosed and repaired promptly — this is a moderate-severity code. Ignoring it can lead to further damage or a failed emissions test. Exact tolerance depends on the model and engine.