P2235

Code

Generic P — Powertrain

O2 Sensor Signal Circuit Shorted to Heater Circuit Bank 2 Sensor 2

Brand: Generic

Type: P — Powertrain

Views: UK: 29 EN: 31 RU: 24

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Page language: EN

Causes

Damaged/chewed wiring harness where signal and heater wires are contacting
Corroded or bent connector terminals causing shorts between pins
Aftermarket or replacement O2 sensor wired incorrectly or with wrong connector
Internal short inside the O2 sensor between heater element and sensing element
Water ingress in the connector or sensor causing conductive path
Previous repair with repaired splice that failed

Symptoms

MIL (Check Engine Light) illuminated
Failed emissions test or readiness monitor incomplete for catalyst/O2 sensor
Stored related DTCs (O2 sensor, heater circuit, or catalyst monitoring codes)
Poor or erratic downstream O2 sensor voltage data on a scan tool
Possible drivability issues are unlikely but may occur depending on vehicle strategy

What to check

Read and record all stored codes and freeze frame data with a scan tool
Monitor live O2 sensor voltage and heater control status for Bank 2 Sensor 2
Visually inspect wiring harness and connectors for damage, burns, corrosion, or water
Wiggle test harness while watching live data to reproduce the fault
Disconnect the sensor and check for continuity/short between signal pin and heater pins
Measure heater resistance and compare to manufacturer specification

Signal parameters

O2 sensor signal (narrowband) typical range: ~0.0–1.0 V (downstream may be relatively steady but still within this range)
Heater circuit supply: switched battery voltage (~12 V) when active or PWM control
Heater resistance (typical): ~2–20 ohms (vehicle/part specific — consult spec)
There should be no measurable continuity (open/infinite resistance) between the sensor signal pin and the heater pins with the sensor disconnected
When ECM drives heater, heater circuit should show supply voltage at the connector or PWM signal at PCM pin

Diagnostic algorithm

Verify the code: erase codes and re-scan to confirm P2235 returns and note any associated codes.
Inspect harness and connector at Bank 2 Sensor 2 for obvious damage, corrosion, melted insulation, or water intrusion. Repair any visible damage.
With ignition off, disconnect the O2 sensor. Using an ohmmeter, check resistance between the sensor signal pin and each heater pin. There should be no continuity. Any continuity indicates internal sensor short or wiring short to heater.
Measure the heater resistance across the heater pins and compare to spec. Extremely low or open readings indicate a failed heater.
Backprobe the sensor connector (or ECM connector if required) and with ignition on, verify heater supply voltage and PCM control signal. Verify the signal circuit has no unintended voltage present (no +12 V or ground on signal pin).
If no short is found at the sensor, perform continuity and short-to-power/ground checks on the wiring from the sensor connector to the PCM to locate a shorted splice or pin. Repair damaged wiring or connectors.
If wiring checks good but continuity existed at the sensor, replace the downstream O2 sensor (Bank 2 Sensor 2) with a correct OEM or correct-spec sensor.
After repair or sensor replacement clear codes, perform a drive cycle and verify that the code does not return and that readiness monitors complete.
If the fault persists and wiring and sensor check good, consider PCM/ECM connector inspection and, as a last resort, module diagnosis by a qualified shop.

Likely causes

Damaged wiring or damaged connector allowing the signal and heater wires to short
Faulty O2 sensor with internal short between heater and sensor signal
Corroded or contaminated connector creating a conductive path

Fault status

⚠️ Status

O2 Sensor Signal Circuit Shorted to Heater Circuit — the PCM detected an electrical short between the post‑catalyst O2 sensor signal wire and its heater circuit on Bank 2 Sensor 2. This may be caused by wiring damage, connector corrosion, or a failed sensor.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.5 hours