P0136 on Subaru vehicles
Post-Cat O2 Sensor Circuit Fault (Bank 1) — what it means on a Subaru, whether it's safe to drive, and the fixes by model and year.
P0136 on a Subaru means post-cat o2 sensor circuit fault (bank 1). Most vehicles stay drivable short-term, but diagnose it promptly. The most common cause is failed bank 1 downstream o2 sensor (typically $150–$450). Pick your Subaru model below for its known failure patterns, recalls, and TSBs.
What does P0136 mean on a Subaru?
P0136 is set when the ECM detects a general circuit fault on the Bank 1 downstream (post-catalyst) oxygen sensor. Unlike the more specific P0137 (low voltage), P0138 (high voltage), or P0140 (no activity), P0136 is the generic circuit code that covers wiring issues, intermittent connection problems, or signals that go outside expected ranges in a way that doesn't fit a more specific fault category.
P0136 is a standardized OBD-II code, so its definition is the same on every Subaru. What differs by model and engine is which cause is most likely — pick your Subaru model below for a diagnosis tuned to its known failure patterns, recalls, and TSBs.
Is it safe to drive a Subaru with P0136?
In most cases a Subaru stays drivable for short trips with P0136 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 P0136 on a Subaru?
| Cause | Likelihood | Estimated repair (USD) |
|---|---|---|
| Failed Bank 1 downstream O2 sensor | Most common | $150–$450 |
| Damaged sensor wiring (chafed against exhaust) | Common | $80–$350 |
| Corroded O2 sensor connector | Common | $30–$200 |
| Exhaust leak upstream of the downstream sensor | Occasional | $100–$500 |
| Damaged or compressed sensor pigtail from a previous repair | Occasional | $80–$300 |
| Failed PCM input (rare) | Rare | $400–$1,500 |
Repair costs are typical US ranges and vary by Subaru 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.
P0136 by Subaru model
Select your Subaru model and year for a P0136 diagnosis tuned to that vehicle's failure patterns, recalls, and TSBs.
Subaru Outback
1,651 NHTSA owner complaints · 24 recalls on record across the years covered below.
Subaru Forester
765 NHTSA owner complaints · 17 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 P0136.
P0136 on other makes
Other codes on Subaru vehicles
P0136 on a Subaru: frequently asked questions
What does diagnostic trouble code P0136 mean on a Subaru?
P0136 is set when the ECM detects a general circuit fault on the Bank 1 downstream (post-catalyst) oxygen sensor. Unlike the more specific P0137 (low voltage), P0138 (high voltage), or P0140 (no activity), P0136 is the generic circuit code that covers wiring issues, intermittent connection problems, or signals that go outside expected ranges in a way that doesn't fit a more specific fault category. P0136 is a standardized OBD-II code, so the definition is the same on every Subaru — which cause is most likely varies by model and engine.
What are the symptoms of P0136 on a Subaru?
Check Engine Light is illuminated. Catalyst readiness monitor will not complete. Possible slight reduction in fuel economy. Often no drivability symptoms. Vehicle will fail emissions / smog testing
What causes P0136 on a Subaru?
Failed Bank 1 downstream O2 sensor (most-common). Damaged sensor wiring (chafed against exhaust) (common). Corroded O2 sensor connector (common). Exhaust leak upstream of the downstream sensor (occasional). Damaged or compressed sensor pigtail from a previous repair (occasional). Failed PCM input (rare) (rare)
Is it safe to drive a Subaru with P0136?
In most cases a Subaru stays drivable for short trips with P0136 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.