Fix P0057: Mechanic’s solutions that WORKED

The code P0057: Heated Oxygen Sensor (HO2S) Heater Circuit Low Voltage Bank 2 Sensor 2 indicates a fault in the vehicle’s oxygen sensor heater circuit, specifically pointing to low voltage in the heater circuit of the oxygen sensor located in Bank 2, Sensor 2. This issue is most commonly caused by a malfunctioning oxygen sensor, wiring problems, or a blown fuse.

P0057 quick overview

Meaning	P0057: Heated Oxygen Sensor (HO2S) Heater Circuit Low Voltage Bank 2 Sensor 2
Is it serious?	Yes, it can affect the vehicle’s fuel efficiency and emissions.
Possible causes	– Faulty oxygen sensor – Blown fuse for the sensor heater circuit – Wiring or connector issues – Faulty Engine Control Module (ECM) – Exhaust leaks near the sensor
How to diagnose?	1. Read the fault code and freeze frame data using an OBD-II scanner. 2. Visually inspect the wiring and connectors related to the O2 sensor. 3. Check the relevant fuses and replace if necessary. 4. Test the resistance and voltage of the O2 sensor heater circuit. 5. Inspect for any exhaust leaks that could affect sensor readings. 6. If all else checks out, consider replacing the oxygen sensor with an OEM part. 7. Reset the ECM and clear the codes to see if the issue persists. 8. If the code returns, further diagnosis of the ECM and related systems may be necessary.

How to fix P0057 – learn from mechanics

I looked into P0057 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Dodge

Vehicle Information 2006 Dodge Dakota SLT 3.7L

Issue + Repair History

• MIL on with codes P0031, P0037, P0051, P0057 indicating issues with all 4 O2 heater circuits
• Vehicle recently from body shop, front damage
• O2 heater resistance tested at PCM, within specs
• All fuses under the hood checked and found to be good

Other OBD2 Codes + Test Results

• p0031- b1s1 heater control low
• p0037- b1s2 heater control low
• p0051- b2s1 heater control low
• p0057- b2s2 heater control low

What are people suggesting to fix issue

• Check all wiring to the O2 sensors from the PCM
• Consider the possibility of a damaged PCM from the crash
• Verify all PCM powers and grounds
• Check for a common ground issue for the O2 sensors
• Look for shorts in the ASD circuit which could fry the PCM

What was the final fix

• After individual testing of each sensor and wire from PCM to sensors, all were found to be okay
• All power and grounds at PCM tested okay
• Advised body shop that PCM replacement might be needed, vehicle was picked up

Case #2: Nissan

Vehicle Information 2005 Nissan Maxima SL 3.5L

Issue + Repair History

• Towed in as a no-start
• No communication with scanners, no check engine light
• Coil fuse blown, replaced but still no start
• Bad computer identified, voltage and grounds checked
• Replaced 3 coils under the intake, 1 bad and another borderline
• Used computer installed and reflashed at the dealer
• MIL on with codes P0057 and P1271 after driving
• Both A/F sensors replaced, but P0057 returned
• Further testing indicated PCM might not release ground circuit properly while driving

Other OBD2 Codes + Test Results

• P0057 – Heated oxygen sensor B2S2
• P1271 – Air fuel sensor bank 1
• P1281 – Air fuel sensor Bank 2
• Fuel Pressure test – 51 psi at idle
• Voltage dropped the affected circuits – Powers and grounds all test good, Proper voltages
• Lab scope mass air flow – Signal is good, also tried swapping out with a known good part
• Checked all powers and grounds to PCM – Everything checks out other than fuse to coils blown
• Smoke tested intake – No leaks detected

What are people suggesting to fix issue

• Check if the heaters are pulsed and if there’s a switching transistor in the PCM
• Use OEM sensors instead of aftermarket
• Follow the code diagnostic fault tree
• Check all connections, especially grounds, around the plenum and negative battery cable
• Use a scope to check the heater control circuit for the rear O2 sensors
• Verify the correct ECM is installed

What was the final fix

• After retesting all wiring to the heated oxygen sensor, replaced the sensors with OEM
• Found that sometimes the PCM would not release the ground circuit while driving
• Replaced the used PCM with another and had it flashed by the dealer
• Extensive road testing did not trip the code again, vehicle returned to the client

Case #3: Jeep

Vehicle Information 2011 Jeep Wrangler Unlimited Sahara 3.8L

Issue + Repair History

• Failed emission test, CEL on
• Unable to clear DTCs P0031, P0051, P0037, P0057, P0158, P0138, P2271, P2273
• Vehicle runs fine with no apparent issues
• Heater circuits tested at 4.4 to 4.5 ohms
• Good ground at all sensors
• Power backprobed for all sensors fluctuates between 1.1 to battery voltage

Other OBD2 Codes + Test Results

• P0031 – O2 sensor B1S1 heater circuit low
• P0051 – O2 sensor B2S1 heater circuit low
• P0037 – O2 sensor B1S2 heater circuit low
• P0057 – O2 sensor B2S2 heater circuit low
• P0158 – O2 sensor B2S2 circuit high
• P0138 – O2 sensor B1S2 circuit high
• P2271 – O2 sensor B1S2 signal stuck rich
• P2273 – O2 sensor B2S2 signal biased rich

What are people suggesting to fix issue

• Replace PCM if heater circuits check OK
• Power up the sensors’ heater circuits through an ammeter to ensure wiring can support the load
• Check fuses and perform voltage drop testing
• Ensure OEM O2 sensors are installed and check wiring for chaffing

What was the final fix

• All O2 sensors were shorted out
• PCM had an internal short on O2 signal terminal
• Replaced PCM and all O2 sensors
• Reprogrammed PCM
• Tested all OK

Case #4: Hyundai

Vehicle Information 2002 Hyundai Santa Fe LX 2.7L

Issue + Repair History

• CEL on with P0057 code (bank 2 sensor 2 heater low)
• O2 sensor heater failed, open circuit
• New O2 sensor installed, heater current flowing, computer controlling ground side
• Code returned on 2nd drive cycle
• Wiring diagrams not matching, causing confusion
• Aftermarket sensor installed, then replaced with OE Hyundai sensor
• New issues arose with four oxygen sensor codes

Other OBD2 Codes + Test Results

• P0037 – Heater control circuit low B1S2
• P0051 – B2S1 (original code)
• P0057 – B2S2
• P1166 – Heated oxygen sensor Bank 1 Adaptation

What are people suggesting to fix issue

• Use OEM sensors
• Check amperage on heater control
• Look for exhaust leaks with a smoke machine
• Check for TSBs regarding a reflash for B2S2 code
• Verify wire colors based on connector pin position/number
• Map O2 sensors by unplugging to see which one drops out

What was the final fix

• Connector pull-out issues resolved with new connectors from the dealer
• Installed OE Hyundai sensor

Case #5: Audi

Vehicle Information 2002 Audi A4 Quattro 3.0L

Symptoms

• Vehicle stalled on road
• Running very rich (fuel out tailpipe)
• MAF reads 0
• Replaced MAF, still 0 reading
• P0261 (cyl 1 injector open)
• P0414, P041 (secondary air injection)
• P445, P2401 (evap system codes)

Computer Codes & Descriptions

• P0030 – O2S11
• P0037 – O2S12
• P0050 – O2S21
• P0057 – O2S22
• P0141 – O2 heater12
• P0161 – O2 heater22

What people are suggesting to fix issue

• Check for rubbed-through wires or harnesses
• Use VW, Audi software for diagnostics (Ross tech or Snap-on)
• Check timing belt for oil contamination
• Inspect the large diaphragm at the rear of the engine for PCV vacuum leak
• Reset ECM by removing both battery terminals and connecting them together
• Check for failures on the intake boot

What was the final fix

• Found #34 engine management fuse blown
• Eventually found an intermittent short in the O2S11 heater
• Replaced O2 sensor (O2S11)
• Vehicle running great after replacing O2 sensor and addressing the blown fuse

Advice	Brief Description of Diagnostic Step
Check O2 Sensor and Heater Circuit	Inspect the oxygen sensor and its heater circuit for faults, including checking for resistance and voltage.
Verify Wiring and Connectors	Examine the wiring and connectors for signs of damage, corrosion, or loose connections.
Use OEM Parts	When replacing sensors, especially O2 sensors, use Original Equipment Manufacturer (OEM) parts to ensure compatibility and proper function.
Check for Software Updates or TSBs	Look for any Technical Service Bulletins (TSBs) or software updates that might address the issue.
Inspect Related Fuses	Check the fuses related to the O2 sensor and its heater circuit for any blown fuses.
Perform a Visual Inspection	Conduct a thorough visual inspection of the affected area for any obvious signs of damage or wear.
Reset ECM if Necessary	Consider resetting the Engine Control Module (ECM) by disconnecting the battery or using a scanner, especially if the vehicle exhibits strange behavior.
Ensure Proper Ground Connections	Verify that the O2 sensor and its heater circuit have proper grounding.
Load Test Circuits	Perform a load test on the circuits to ensure they can handle the required current without voltage drops.
Check for Exhaust Leaks	Inspect the exhaust system for any leaks that could affect O2 sensor readings.