Code
P0159
Generic
P — Powertrain
O2 Sensor Circuit Slow Response Bank 2 Sensor 2
Views:
UK: 16
EN: 30
RU: 23
AI status
Completed
Completed
100%
Causes
- Aging or contaminated O2 sensor (zirc‑type or wideband cell degradation)
- Heater circuit failure (open, short, blown fuse, relay, or driver)
- Damaged wiring or poor connector contact (opens, shorts to ground/voltage, high resistance)
- Exhaust leaks near the sensor or between banks
- Contamination by oil, coolant, silicone, or fuel additives
- Excessive unburned fuel / misfires or lean conditions affecting sensor loading
Symptoms
- Check Engine Light (MIL) illuminated
- Possible poor fuel economy
- Failed emissions test (exhaust not within required limits)
- Rough idle, hesitation, or drivability complaints if upstream issues also present
- Stored freeze‑frame data showing long sensor response time or abnormal fuel trims
What to check
- Retrieve freeze‑frame data and all stored/PENDING codes; check readiness monitors
- Scan tool — monitor Bank 2 Sensor 2 live data while commanding changes to air-fuel (snap throttle or short throttle): observe voltage/current response and switching rate
- Monitor upstream (Bank 2 Sensor 1) and downstream (Bank 2 Sensor 2) oxygen sensor waveforms together
- Check O2 sensor heater circuit: verify fuse/relay and PCM control, check for 12 V feed and switched ground, measure heater resistance at the sensor
- Inspect wiring and connector for corrosion, bent pins, heat damage, or water intrusion; wiggle harness while monitoring for changes
- Check for exhaust leaks and physical damage to the sensor or bung
Signal parameters
- Narrowband zirconia (typical downstream behavior): voltage nominally switches between ~0.1 V (lean) and ~0.9 V (rich); downstream sensor should be relatively steady but still respond to changes; slow response means transitions take longer than expected (several hundred ms to seconds)
- Upstream (for comparison): rapid switching ~1–2 Hz at steady state (0.1–0.9 V). Downstream will normally be steadier; large lag indicates problem
- Heater circuit (typical): cold sensor heater resistance commonly in the ~3–20 ohm range (varies by sensor). Heater supply ~12 V with driver current up to 0.5–2 A. Consult vehicle/service manual for exact values
- Wideband sensors: signal and heater/current values differ; refer to OEM specs for expected volts/amps and response time
Diagnostic algorithm
- Verify the code, note freeze frame and related codes. Don’t replace sensor immediately. 2) Visual inspection: check sensor, harness, connector, and exhaust for leaks or damage. 3) Check fuses/relays for heater circuit and verify PCM ground/power. 4) Measure heater resistance at the sensor and verify battery voltage present at heater feed with key ON. If heater is open or out of spec, replace sensor. 5) Use a scan tool to observe Bank 2 Sensor 1 and Sensor 2 live data. Induce a rapid change in AFR (snap throttle or slight load change) and observe response time of Sensor 2. 6) Backprobe heater control (or use lab scope) to verify PCM is driving heater properly. 7) Perform continuity and resistance checks on wiring from sensor to PCM; check for shorts to ground or B+. Repair as needed. 8) If wiring and heater are good but response is slow, inspect for contamination or catalytic converter issues (a clogged or poisoned converter can change downstream response). 9) If available and safe, swap the suspect sensor with the equivalent sensor on the other bank (if same type) to see if the code follows the sensor. 10) After repairs, clear codes and perform a road test/drive cycle to confirm response and readiness. If sensor still slow and harness and PCM checks are good, replace sensor and retest.
Likely causes
- Worn/contaminated downstream O2 sensor (most likely)
- Heater circuit fault preventing the sensor from reaching operating temperature
- Intermittent wiring/connector fault at sensor or in harness
- Exhaust leak or engine running condition masking true sensor response
- Less likely: PCM driver fault
Fault status
Status
PCM logged P0159 when it detected the Bank 2 Sensor 2 oxygen sensor’s response time was slower than the threshold during self‑diagnosis. The fault may be current or historic; further testing of sensor, heater, wiring, exhaust and engine operating conditions is required.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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Code
P0159
GWM
P — Powertrain
- The oxygen sensor responds late (bank 2, sensor 2)
Views:
UK: 2
EN: 6
RU: 2
AI status
Completed
Completed
100%
Causes
- Aging or contaminated O2 sensor (zirc‑type or wideband cell degradation)
- Heater circuit failure (open, short, blown fuse, relay, or driver)
- Damaged wiring or poor connector contact (opens, shorts to ground/voltage, high resistance)
- Exhaust leaks near the sensor or between banks
- Contamination by oil, coolant, silicone, or fuel additives
- Excessive unburned fuel / misfires or lean conditions affecting sensor loading
Symptoms
- Check Engine Light (MIL) illuminated
- Possible poor fuel economy
- Failed emissions test (exhaust not within required limits)
- Rough idle, hesitation, or drivability complaints if upstream issues also present
- Stored freeze‑frame data showing long sensor response time or abnormal fuel trims
What to check
- Retrieve freeze‑frame data and all stored/PENDING codes; check readiness monitors
- Scan tool — monitor Bank 2 Sensor 2 live data while commanding changes to air-fuel (snap throttle or short throttle): observe voltage/current response and switching rate
- Monitor upstream (Bank 2 Sensor 1) and downstream (Bank 2 Sensor 2) oxygen sensor waveforms together
- Check O2 sensor heater circuit: verify fuse/relay and PCM control, check for 12 V feed and switched ground, measure heater resistance at the sensor
- Inspect wiring and connector for corrosion, bent pins, heat damage, or water intrusion; wiggle harness while monitoring for changes
- Check for exhaust leaks and physical damage to the sensor or bung
Signal parameters
- Narrowband zirconia (typical downstream behavior): voltage nominally switches between ~0.1 V (lean) and ~0.9 V (rich); downstream sensor should be relatively steady but still respond to changes; slow response means transitions take longer than expected (several hundred ms to seconds)
- Upstream (for comparison): rapid switching ~1–2 Hz at steady state (0.1–0.9 V). Downstream will normally be steadier; large lag indicates problem
- Heater circuit (typical): cold sensor heater resistance commonly in the ~3–20 ohm range (varies by sensor). Heater supply ~12 V with driver current up to 0.5–2 A. Consult vehicle/service manual for exact values
- Wideband sensors: signal and heater/current values differ; refer to OEM specs for expected volts/amps and response time
Diagnostic algorithm
- Verify the code, note freeze frame and related codes. Don’t replace sensor immediately. 2) Visual inspection: check sensor, harness, connector, and exhaust for leaks or damage. 3) Check fuses/relays for heater circuit and verify PCM ground/power. 4) Measure heater resistance at the sensor and verify battery voltage present at heater feed with key ON. If heater is open or out of spec, replace sensor. 5) Use a scan tool to observe Bank 2 Sensor 1 and Sensor 2 live data. Induce a rapid change in AFR (snap throttle or slight load change) and observe response time of Sensor 2. 6) Backprobe heater control (or use lab scope) to verify PCM is driving heater properly. 7) Perform continuity and resistance checks on wiring from sensor to PCM; check for shorts to ground or B+. Repair as needed. 8) If wiring and heater are good but response is slow, inspect for contamination or catalytic converter issues (a clogged or poisoned converter can change downstream response). 9) If available and safe, swap the suspect sensor with the equivalent sensor on the other bank (if same type) to see if the code follows the sensor. 10) After repairs, clear codes and perform a road test/drive cycle to confirm response and readiness. If sensor still slow and harness and PCM checks are good, replace sensor and retest.
Likely causes
- Worn/contaminated downstream O2 sensor (most likely)
- Heater circuit fault preventing the sensor from reaching operating temperature
- Intermittent wiring/connector fault at sensor or in harness
- Exhaust leak or engine running condition masking true sensor response
- Less likely: PCM driver fault
Fault status
Status
PCM logged P0159 when it detected the Bank 2 Sensor 2 oxygen sensor’s response time was slower than the threshold during self‑diagnosis. The fault may be current or historic; further testing of sensor, heater, wiring, exhaust and engine operating conditions is required.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
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Code
P0159
HUMMER
P — Powertrain
Heated Oxygen Sensor (HO2S) Slow Response Bank 2 Sensor 2
Views:
UK: 9
EN: 15
RU: 10
AI status
Completed
Completed
100%
Causes
- Aging or contaminated O2 sensor (zirc‑type or wideband cell degradation)
- Heater circuit failure (open, short, blown fuse, relay, or driver)
- Damaged wiring or poor connector contact (opens, shorts to ground/voltage, high resistance)
- Exhaust leaks near the sensor or between banks
- Contamination by oil, coolant, silicone, or fuel additives
- Excessive unburned fuel / misfires or lean conditions affecting sensor loading
Symptoms
- Check Engine Light (MIL) illuminated
- Possible poor fuel economy
- Failed emissions test (exhaust not within required limits)
- Rough idle, hesitation, or drivability complaints if upstream issues also present
- Stored freeze‑frame data showing long sensor response time or abnormal fuel trims
What to check
- Retrieve freeze‑frame data and all stored/PENDING codes; check readiness monitors
- Scan tool — monitor Bank 2 Sensor 2 live data while commanding changes to air-fuel (snap throttle or short throttle): observe voltage/current response and switching rate
- Monitor upstream (Bank 2 Sensor 1) and downstream (Bank 2 Sensor 2) oxygen sensor waveforms together
- Check O2 sensor heater circuit: verify fuse/relay and PCM control, check for 12 V feed and switched ground, measure heater resistance at the sensor
- Inspect wiring and connector for corrosion, bent pins, heat damage, or water intrusion; wiggle harness while monitoring for changes
- Check for exhaust leaks and physical damage to the sensor or bung
Signal parameters
- Narrowband zirconia (typical downstream behavior): voltage nominally switches between ~0.1 V (lean) and ~0.9 V (rich); downstream sensor should be relatively steady but still respond to changes; slow response means transitions take longer than expected (several hundred ms to seconds)
- Upstream (for comparison): rapid switching ~1–2 Hz at steady state (0.1–0.9 V). Downstream will normally be steadier; large lag indicates problem
- Heater circuit (typical): cold sensor heater resistance commonly in the ~3–20 ohm range (varies by sensor). Heater supply ~12 V with driver current up to 0.5–2 A. Consult vehicle/service manual for exact values
- Wideband sensors: signal and heater/current values differ; refer to OEM specs for expected volts/amps and response time
Diagnostic algorithm
- Verify the code, note freeze frame and related codes. Don’t replace sensor immediately. 2) Visual inspection: check sensor, harness, connector, and exhaust for leaks or damage. 3) Check fuses/relays for heater circuit and verify PCM ground/power. 4) Measure heater resistance at the sensor and verify battery voltage present at heater feed with key ON. If heater is open or out of spec, replace sensor. 5) Use a scan tool to observe Bank 2 Sensor 1 and Sensor 2 live data. Induce a rapid change in AFR (snap throttle or slight load change) and observe response time of Sensor 2. 6) Backprobe heater control (or use lab scope) to verify PCM is driving heater properly. 7) Perform continuity and resistance checks on wiring from sensor to PCM; check for shorts to ground or B+. Repair as needed. 8) If wiring and heater are good but response is slow, inspect for contamination or catalytic converter issues (a clogged or poisoned converter can change downstream response). 9) If available and safe, swap the suspect sensor with the equivalent sensor on the other bank (if same type) to see if the code follows the sensor. 10) After repairs, clear codes and perform a road test/drive cycle to confirm response and readiness. If sensor still slow and harness and PCM checks are good, replace sensor and retest.
Likely causes
- Worn/contaminated downstream O2 sensor (most likely)
- Heater circuit fault preventing the sensor from reaching operating temperature
- Intermittent wiring/connector fault at sensor or in harness
- Exhaust leak or engine running condition masking true sensor response
- Less likely: PCM driver fault
Fault status
Status
PCM logged P0159 when it detected the Bank 2 Sensor 2 oxygen sensor’s response time was slower than the threshold during self‑diagnosis. The fault may be current or historic; further testing of sensor, heater, wiring, exhaust and engine operating conditions is required.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
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Code
P0159
LAND ROVER
P — Powertrain
Heated oxygen sensor circuit slow response bank 2 sensor 2
Views:
UK: 6
EN: 13
RU: 7
AI status
Completed
Completed
100%
Causes
- Aging or contaminated O2 sensor (zirc‑type or wideband cell degradation)
- Heater circuit failure (open, short, blown fuse, relay, or driver)
- Damaged wiring or poor connector contact (opens, shorts to ground/voltage, high resistance)
- Exhaust leaks near the sensor or between banks
- Contamination by oil, coolant, silicone, or fuel additives
- Excessive unburned fuel / misfires or lean conditions affecting sensor loading
Symptoms
- Check Engine Light (MIL) illuminated
- Possible poor fuel economy
- Failed emissions test (exhaust not within required limits)
- Rough idle, hesitation, or drivability complaints if upstream issues also present
- Stored freeze‑frame data showing long sensor response time or abnormal fuel trims
What to check
- Retrieve freeze‑frame data and all stored/PENDING codes; check readiness monitors
- Scan tool — monitor Bank 2 Sensor 2 live data while commanding changes to air-fuel (snap throttle or short throttle): observe voltage/current response and switching rate
- Monitor upstream (Bank 2 Sensor 1) and downstream (Bank 2 Sensor 2) oxygen sensor waveforms together
- Check O2 sensor heater circuit: verify fuse/relay and PCM control, check for 12 V feed and switched ground, measure heater resistance at the sensor
- Inspect wiring and connector for corrosion, bent pins, heat damage, or water intrusion; wiggle harness while monitoring for changes
- Check for exhaust leaks and physical damage to the sensor or bung
Signal parameters
- Narrowband zirconia (typical downstream behavior): voltage nominally switches between ~0.1 V (lean) and ~0.9 V (rich); downstream sensor should be relatively steady but still respond to changes; slow response means transitions take longer than expected (several hundred ms to seconds)
- Upstream (for comparison): rapid switching ~1–2 Hz at steady state (0.1–0.9 V). Downstream will normally be steadier; large lag indicates problem
- Heater circuit (typical): cold sensor heater resistance commonly in the ~3–20 ohm range (varies by sensor). Heater supply ~12 V with driver current up to 0.5–2 A. Consult vehicle/service manual for exact values
- Wideband sensors: signal and heater/current values differ; refer to OEM specs for expected volts/amps and response time
Diagnostic algorithm
- Verify the code, note freeze frame and related codes. Don’t replace sensor immediately. 2) Visual inspection: check sensor, harness, connector, and exhaust for leaks or damage. 3) Check fuses/relays for heater circuit and verify PCM ground/power. 4) Measure heater resistance at the sensor and verify battery voltage present at heater feed with key ON. If heater is open or out of spec, replace sensor. 5) Use a scan tool to observe Bank 2 Sensor 1 and Sensor 2 live data. Induce a rapid change in AFR (snap throttle or slight load change) and observe response time of Sensor 2. 6) Backprobe heater control (or use lab scope) to verify PCM is driving heater properly. 7) Perform continuity and resistance checks on wiring from sensor to PCM; check for shorts to ground or B+. Repair as needed. 8) If wiring and heater are good but response is slow, inspect for contamination or catalytic converter issues (a clogged or poisoned converter can change downstream response). 9) If available and safe, swap the suspect sensor with the equivalent sensor on the other bank (if same type) to see if the code follows the sensor. 10) After repairs, clear codes and perform a road test/drive cycle to confirm response and readiness. If sensor still slow and harness and PCM checks are good, replace sensor and retest.
Likely causes
- Worn/contaminated downstream O2 sensor (most likely)
- Heater circuit fault preventing the sensor from reaching operating temperature
- Intermittent wiring/connector fault at sensor or in harness
- Exhaust leak or engine running condition masking true sensor response
- Less likely: PCM driver fault
Fault status
Status
PCM logged P0159 when it detected the Bank 2 Sensor 2 oxygen sensor’s response time was slower than the threshold during self‑diagnosis. The fault may be current or historic; further testing of sensor, heater, wiring, exhaust and engine operating conditions is required.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 UAH
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Code
P0159
MITSUBISHI
P — Powertrain
Oxygen sensor2(rear) response
Views:
UK: 10
EN: 15
RU: 13
AI status
Completed
Completed
100%
Causes
- Aging or contaminated O2 sensor (zirc‑type or wideband cell degradation)
- Heater circuit failure (open, short, blown fuse, relay, or driver)
- Damaged wiring or poor connector contact (opens, shorts to ground/voltage, high resistance)
- Exhaust leaks near the sensor or between banks
- Contamination by oil, coolant, silicone, or fuel additives
- Excessive unburned fuel / misfires or lean conditions affecting sensor loading
Symptoms
- Check Engine Light (MIL) illuminated
- Possible poor fuel economy
- Failed emissions test (exhaust not within required limits)
- Rough idle, hesitation, or drivability complaints if upstream issues also present
- Stored freeze‑frame data showing long sensor response time or abnormal fuel trims
What to check
- Retrieve freeze‑frame data and all stored/PENDING codes; check readiness monitors
- Scan tool — monitor Bank 2 Sensor 2 live data while commanding changes to air-fuel (snap throttle or short throttle): observe voltage/current response and switching rate
- Monitor upstream (Bank 2 Sensor 1) and downstream (Bank 2 Sensor 2) oxygen sensor waveforms together
- Check O2 sensor heater circuit: verify fuse/relay and PCM control, check for 12 V feed and switched ground, measure heater resistance at the sensor
- Inspect wiring and connector for corrosion, bent pins, heat damage, or water intrusion; wiggle harness while monitoring for changes
- Check for exhaust leaks and physical damage to the sensor or bung
Signal parameters
- Narrowband zirconia (typical downstream behavior): voltage nominally switches between ~0.1 V (lean) and ~0.9 V (rich); downstream sensor should be relatively steady but still respond to changes; slow response means transitions take longer than expected (several hundred ms to seconds)
- Upstream (for comparison): rapid switching ~1–2 Hz at steady state (0.1–0.9 V). Downstream will normally be steadier; large lag indicates problem
- Heater circuit (typical): cold sensor heater resistance commonly in the ~3–20 ohm range (varies by sensor). Heater supply ~12 V with driver current up to 0.5–2 A. Consult vehicle/service manual for exact values
- Wideband sensors: signal and heater/current values differ; refer to OEM specs for expected volts/amps and response time
Diagnostic algorithm
- Verify the code, note freeze frame and related codes. Don’t replace sensor immediately. 2) Visual inspection: check sensor, harness, connector, and exhaust for leaks or damage. 3) Check fuses/relays for heater circuit and verify PCM ground/power. 4) Measure heater resistance at the sensor and verify battery voltage present at heater feed with key ON. If heater is open or out of spec, replace sensor. 5) Use a scan tool to observe Bank 2 Sensor 1 and Sensor 2 live data. Induce a rapid change in AFR (snap throttle or slight load change) and observe response time of Sensor 2. 6) Backprobe heater control (or use lab scope) to verify PCM is driving heater properly. 7) Perform continuity and resistance checks on wiring from sensor to PCM; check for shorts to ground or B+. Repair as needed. 8) If wiring and heater are good but response is slow, inspect for contamination or catalytic converter issues (a clogged or poisoned converter can change downstream response). 9) If available and safe, swap the suspect sensor with the equivalent sensor on the other bank (if same type) to see if the code follows the sensor. 10) After repairs, clear codes and perform a road test/drive cycle to confirm response and readiness. If sensor still slow and harness and PCM checks are good, replace sensor and retest.
Likely causes
- Worn/contaminated downstream O2 sensor (most likely)
- Heater circuit fault preventing the sensor from reaching operating temperature
- Intermittent wiring/connector fault at sensor or in harness
- Exhaust leak or engine running condition masking true sensor response
- Less likely: PCM driver fault
Fault status
Status
PCM logged P0159 when it detected the Bank 2 Sensor 2 oxygen sensor’s response time was slower than the threshold during self‑diagnosis. The fault may be current or historic; further testing of sensor, heater, wiring, exhaust and engine operating conditions is required.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
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