P1135

Code

TOYOTA P — Powertrain

Air/Fuel Sensor Heater Circuit Response Bank 1 Sensor 1

Brand: TOYOTA

Type: P — Powertrain

Views: UK: 40 EN: 68 RU: 50

AI status

Completed

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Page language: EN

Causes

Open or shorted heater wiring (connector damage, chafing, broken conductor)
Corroded or loose heater connector/pins
Failed A/F (wideband) sensor heater element
Blown fuse or bad relay supplying heater circuit
High-resistance connection or poor ground
Faulty PCM (rare) or incorrect PCM control signal

Symptoms

Malfunction Indicator Lamp (MIL/Check Engine) illuminated
Poor fuel economy or drivability issues (rough idle, hesitation)
Hard starting, especially when cold
Failed emissions test or elevated tailpipe emissions
Longer warm-up time for the A/F sensor to reach operating temperature

What to check

Scan for freeze frame data and pending codes; note if code is confirmed or intermittent
Visual inspection of harness and connector at Bank 1 Sensor 1 for corrosion, heat damage, or disconnection
Check related fuses/relays that feed the sensor heater circuit
Backprobe heater supply/ground pins with key ON to verify voltage and ground presence
Measure heater element resistance with sensor disconnected (compare to spec)
Check for continuity and shorts to ground/12V in heater wires to the PCM

Signal parameters

Heater supply voltage: ~battery voltage (~11–14 V) when heater is commanded ON (varies by model)
Heater current draw: typically in the 0.5–3 A range when active (specific values vary by sensor)
Heater element resistance (sensor removed): usually low — single digit to low tens of ohms (consult vehicle service manual for exact spec)
A/F sensor output (sensor warm): variable voltage/current signal depending on design — should respond quickly once heated
Expected heater warm-up: sensor should reach operating temperature within a few seconds to a minute after command (varies by design)

Diagnostic algorithm

Retrieve codes and live data; record freeze frame. Verify P1135 is current and note any related codes (other O2/A/F sensor codes).
Visually inspect Bank 1 Sensor 1 connector and wiring for damage, corrosion, or pin push-out. Repair any obvious problems.
Check fuses/relays that feed the sensor heaters. Replace any blown fuses and retest.
With ignition OFF, disconnect sensor. Measure heater element resistance across heater terminals. Compare to TOYOTA spec; replace sensor if open or out of range.
With connector reconnected, backprobe heater power lead(s) with key ON (engine OFF) and with engine running as required. Confirm battery voltage at supply and good ground at return when heater is commanded.
Use a scan tool to command the heater ON (if supported) and monitor heater voltage/current PIDs and whether the PCM reports heater reaching temperature. Note abnormal readings.
Check continuity from the sensor heater terminals back to the PCM pins. Check for shorts to chassis ground and to battery positive. Repair any wiring faults.
If wiring and power are good but heater element is within spec, consider replacing the A/F sensor. After replacement, clear codes and perform drive cycle to confirm resolution.
If new sensor fails similarly and wiring is good, test PCM heater driver output for proper switching. Replace PCM only after verifying all wiring and sensors are good.
After repairs, clear codes, perform functional test and full drive/ready cycle; verify P1135 does not return.

Likely causes

Corroded/loose connector at Bank 1 Sensor 1
Open heater element inside the A/F sensor
Short to ground or short to voltage in heater supply circuit
Blown fuse for sensor heaters or related power feed
High resistance in harness or poor ground causing slow heat-up
PCM output/driver failure (least likely)

Fault status

⚠️ Status

PCM detected abnormal response from air/fuel sensor heater circuit (Bank 1 Sensor 1). Heater not reaching expected temperature or circuit not responding.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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P1135 — Air/Fuel Sensor Heater Circuit Response Bank 1 Sensor 1