If your OBD-II scanner displays P0059, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected that the heater resistance of the heated oxygen sensor (HO2S) on Bank 2 Sensor 1 is outside the manufacturer’s expected operating range.
The generic SAE definition for P0059 is:
HO2S Heater Resistance Bank 2 Sensor 1
Unlike heater control circuit codes such as P0050, P0051, and P0052, which monitor voltage and current in the heater circuit, P0059 specifically monitors the electrical resistance of the heater element inside the oxygen sensor itself.
Bank 2 Sensor 1 is the upstream oxygen sensor, located before the catalytic converter on the side of the engine opposite cylinder number one. Because this sensor plays a major role in fuel control, a failing heater can delay closed-loop operation and increase emissions during cold starts.
Depending on the manufacturer, this sensor may also be called the:
- Heated Oxygen Sensor (HO2S)
- Air/Fuel Ratio (A/F) Sensor
- Wideband Oxygen Sensor
- Lambda Sensor
- Front Oxygen Sensor
- Upstream Oxygen Sensor
- Pre-Catalytic Converter Oxygen Sensor
Common causes of P0059 include:
- Aging heater element
- Failed oxygen sensor
- Open heater circuit
- High heater resistance
- Corroded connector
- Damaged wiring
- Incorrect replacement sensor
- Low battery voltage
- Failed relay
- ECM driver fault (rare)
Although P0059 usually won’t cause severe drivability problems, it can reduce fuel economy, increase cold-start emissions, and eventually trigger additional oxygen sensor or catalyst-related diagnostic trouble codes.
For additional diagnostic information, visit:
- Complete OBD-II Code Library: https://my.prostreetonline.com/dtc-obdii/
- Body B-Code Library: https://my.prostreetonline.com/dtc-doctor/b-code-obd-ii-codes/
- Chassis C-Code Library: https://my.prostreetonline.com/dtc-doctor/c-code-obd-ii-codes/
P0059 Quick Facts
| Item | Information |
|---|---|
| OBD-II Code | P0059 |
| Description | HO2S Heater Resistance Bank 2 Sensor 1 |
| Category | Powertrain |
| System | Fuel Control / Emissions |
| Sensor | Bank 2 Sensor 1 |
| Sensor Location | Upstream (Before Catalytic Converter) |
| Severity | Low to Moderate |
| Safe to Drive? | Usually |
| Typical Repair Cost | $100–600 |
What Does P0059 Mean?
P0059 indicates the ECM has determined that the electrical resistance of the heater inside the Bank 2 Sensor 1 oxygen sensor is outside the manufacturer’s calibrated specification.
Every heated oxygen sensor contains an electric heating element that rapidly warms the sensing element after startup.
The ECM continuously monitors heater resistance because it provides valuable information about the condition of the heater itself.
If resistance becomes:
- Too high
- Too low
- Completely open
- Intermittent
the ECM stores P0059.
Unlike P0050-series codes, this diagnostic evaluates heater condition, not simply whether the heater circuit is functioning electrically.
What Is Bank 2 Sensor 1?
Bank 2 is the side of the engine that does not contain cylinder number one.
Sensor 1 is located before the catalytic converter.
This upstream oxygen sensor is responsible for:
- Fuel trim corrections
- Closed-loop fuel control
- Air/fuel ratio monitoring
- Emissions reduction
- Catalytic converter protection
Because it directly influences fuel delivery, a malfunctioning upstream sensor has a much greater effect on engine operation than a downstream sensor.
What Is Heater Resistance?
The heater inside every oxygen sensor contains a resistance element that converts electrical energy into heat.
As the heater ages:
- Resistance changes
- Current flow changes
- Warm-up slows
- Heater efficiency decreases
The ECM monitors these changes because they often indicate a heater nearing failure.
Much like the heating element inside a toaster or electric stove, the heater doesn’t always fail instantly. Instead, its electrical characteristics gradually drift until they fall outside acceptable limits.
Why Does the Heater Matter?
Modern emissions systems require the upstream oxygen sensor to become operational within seconds after startup.
The heater allows the ECM to:
- Enter closed-loop fuel control quickly
- Improve fuel economy
- Reduce cold-start emissions
- Protect the catalytic converter
- Improve engine performance
Without the heater, the ECM must wait until exhaust heat alone warms the sensor.
How the ECM Monitors Heater Resistance
During self-tests, the ECM monitors:
- Heater resistance
- Current draw
- Supply voltage
- Warm-up rate
- Sensor response time
If the measured heater resistance falls outside the manufacturer’s specification, P0059 is stored.
Unlike heater circuit faults, resistance faults may occur even when the wiring and electrical circuit appear to function normally.
P0059 vs Related Heater Codes
| Code | Description |
| P0050 | Heater Control Circuit Bank 2 Sensor 1 |
| P0051 | Heater Control Circuit Low Bank 2 Sensor 1 |
| P0052 | Heater Control Circuit High Bank 2 Sensor 1 |
| P0053 | Heater Resistance Bank 1 Sensor 1 |
| P0059 | Heater Resistance Bank 2 Sensor 1 |
Generally:
- P0050-P0052 monitor heater circuit operation.
- P0059 evaluates the heater element itself.
Symptoms of P0059
Common symptoms include:
- Check Engine Light
- Reduced fuel economy
- Increased emissions
- Rough cold idle
- Cold hesitation
- Delayed closed-loop operation
- Failed emissions inspection
- Rich air/fuel mixture during warm-up
Some vehicles may exhibit no noticeable symptoms after reaching operating temperature.
Common Causes of P0059
1. Aging Heater Element
Repeated heating and cooling cycles gradually change heater resistance.
This is the most common cause.
2. Failed Oxygen Sensor
Internal heater deterioration eventually places resistance outside specification.
Replacement is usually required.
3. Open Heater Element
The heater may become internally open.
The ECM immediately detects abnormal resistance.
4. Incorrect Replacement Sensor
Universal oxygen sensors often use heater elements with different resistance values than OEM components.
Always use a quality direct-fit sensor.
5. Corroded Connector
Inspect for:
- Green corrosion
- Loose terminals
- Moisture
- Bent pins
- Broken connector locks
Corrosion increases electrical resistance.
6. Damaged Wiring
Inspect for:
- Heat damage
- Broken conductors
- Chafed insulation
- Previous repair splices
- Rodent damage
7. Poor Ground
Weak grounds increase resistance throughout the heater circuit.
Verify all engine and chassis grounds.
8. Low Battery Voltage
Weak charging systems can interfere with heater diagnostics.
Inspect:
- Battery
- Alternator
- Battery terminals
- Engine grounds
9. Failed Heater Relay
Some manufacturers power multiple heater circuits using one relay.
A weak relay may reduce heater performance.
10. ECM Driver Failure
Rare.
Only suspect the ECM after verifying:
- Heater resistance
- Wiring
- Power supply
- Connectors
- Relay operation
Is P0059 Serious?
P0059 is considered a low to moderate severity diagnostic trouble code.
Most vehicles remain safe to drive.
However, delaying repairs may result in:
- Reduced fuel economy
- Increased emissions
- Failed emissions testing
- Additional oxygen sensor codes
- Catalyst stress
Can You Drive With P0059?
Yes.
Most vehicles remain drivable.
However, because this is an upstream oxygen sensor, prolonged operation may affect fuel trims more than similar downstream heater faults.
In other words, your engine will usually keep running just fine—but it may spend a little longer every morning wondering exactly how much fuel it should be using.
How to Diagnose P0059
Step 1: Scan for Additional Codes
Look for:
- P0050
- P0051
- P0052
- P0155
- Fuel trim codes
- Catalyst efficiency codes
Record freeze-frame data.
Step 2: Verify Bank 2 Sensor 1
Confirm:
- Cylinder number one
- Bank 2
- Upstream oxygen sensor
Replacing the wrong sensor remains one of the most common oxygen sensor repair mistakes.
Step 3: Inspect Wiring
Look for:
- Melted insulation
- Chafed wiring
- Heat damage
- Broken conductors
- Previous repairs
Step 4: Inspect Connector
Inspect for:
- Corrosion
- Moisture
- Loose terminals
- Bent pins
- Broken locks
Step 5: Measure Heater Resistance
Disconnect the oxygen sensor.
Measure resistance across the heater terminals.
Possible results:
- Infinite resistance
- Excessively high resistance
- Very low resistance
- Normal resistance
Always compare readings with manufacturer specifications.
Step 6: Verify Power Supply
Check:
- Battery voltage
- Heater fuse
- Relay operation
- Ground integrity
Step 7: Perform Voltage Drop Testing
Measure voltage drop across:
- Heater power wire
- Ground circuit
- Fuse
- Relay
- Connectors
High-resistance circuits often appear normal during simple continuity testing.
Step 8: Compare With Bank 1 Sensor 1
If both upstream sensors use identical heater elements, compare:
- Resistance
- Current draw
- Warm-up rate
Large differences often identify the faulty sensor.
Step 9: Replace the Sensor if Necessary
If heater resistance falls outside specification, replace Bank 2 Sensor 1 with an OEM-quality direct-fit oxygen sensor.
Step 10: Verify Repairs
After repairs:
- Clear diagnostic trouble codes.
- Perform a cold start.
- Monitor heater operation.
- Confirm closed-loop operation.
- Complete an OBD-II drive cycle.
- Verify P0059 does not return.
Common Repairs and Costs
| Repair | Estimated Cost |
| Oxygen sensor replacement | $150–500 |
| Wiring repair | $100–400 |
| Connector replacement | $75–250 |
| Heater relay replacement | $50–200 |
| Fuse replacement | $10–50 |
| Battery or charging repair | $150–400 |
| ECM replacement | $1,000–2,500+ |
Common Diagnostic Mistakes
Avoid these common mistakes:
- Replacing Bank 1 instead of Bank 2
- Installing universal oxygen sensors
- Ignoring connector corrosion
- Skipping voltage-drop testing
- Assuming the heater circuit is faulty when only the heater element has failed
- Replacing the ECM before testing the sensor
Vehicles Commonly Affected
P0059 commonly appears on:
- Chevrolet
- GMC
- Ford
- Dodge
- Chrysler
- Jeep
- Toyota
- Lexus
- Honda
- Acura
- Nissan
- Infiniti
- Hyundai
- Kia
- Subaru
- Volkswagen
- Audi
- BMW
- Mercedes-Benz
- Volvo
Exact heater resistance specifications vary by manufacturer.
How to Prevent P0059
Reduce the likelihood of P0059 by:
- Using OEM-quality oxygen sensors
- Keeping heat shields installed
- Preventing oil and coolant leaks
- Inspecting wiring during exhaust repairs
- Maintaining battery and charging system health
- Cleaning electrical connectors
- Avoiding universal splice-in sensors
Frequently Asked Questions
What does P0059 mean?
P0059 indicates the heater resistance of the Bank 2 Sensor 1 oxygen sensor is outside manufacturer specifications.
Is P0059 serious?
Usually not.
However, repairs should be completed promptly to restore proper fuel control and emissions performance.
Can I drive with P0059?
Yes.
Most vehicles remain safe to drive.
What causes P0059?
The most common causes include:
- Aging heater element
- Failed oxygen sensor
- Damaged wiring
- Corroded connector
- Incorrect replacement sensor
Will replacing the oxygen sensor fix P0059?
In most cases, yes.
However, the wiring and connectors should always be inspected first.
Is P0059 the same as P0050?
No.
P0050 monitors the heater control circuit.
P0059 monitors the heater element’s resistance.
Does P0059 affect fuel economy?
Yes.
Delayed closed-loop operation may increase fuel consumption during engine warm-up.
Can P0059 cause a failed emissions inspection?
Yes.
Improper heater operation can delay readiness monitors and increase emissions.
Final Thoughts
The P0059 code indicates the ECM has detected abnormal heater resistance in the Bank 2 Sensor 1 oxygen sensor. Unlike general heater circuit faults, this code evaluates the health of the heater element itself and often identifies a failing oxygen sensor before complete heater failure occurs.
In most cases, replacing the upstream oxygen sensor resolves the issue, but damaged wiring, corroded connectors, poor grounds, and incorrect replacement sensors should always be ruled out first. Proper diagnosis helps restore rapid closed-loop operation, improve fuel economy, reduce emissions, and prevent additional oxygen sensor or catalyst-related trouble codes.
Related Articles
Bank 2 Sensor 1 Heater Codes
- P0050 Code Explained: HO2S Heater Control Circuit Bank 2 Sensor 1
- P0051 Code Explained: HO2S Heater Control Circuit Low Bank 2 Sensor 1
- P0052 Code Explained: HO2S Heater Control Circuit High Bank 2 Sensor 1
Heater Resistance Codes
- P0053 Code Explained: HO2S Heater Resistance Bank 1 Sensor 1
- P0054 Code Explained: HO2S Heater Resistance Bank 1 Sensor 2
- P0055 Code Explained: HO2S Heater Resistance Bank 2 Sensor 2
Browse the complete Pro Street diagnostic libraries:
- Complete OBD-II Guide: https://my.prostreetonline.com/dtc-obdii/
- B-Code Guide: https://my.prostreetonline.com/dtc-doctor/b-code-obd-ii-codes/
- C-Code Guide: https://my.prostreetonline.com/dtc-doctor/c-code-obd-ii-codes/
