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DTC codes / Jaguar codes / P1190

P1190 · JaguarO2 Sensor Heater Circuit Low Resistance Fault 2

P1190 on a Jaguar means the engine control module has detected that the heater element inside a specific oxygen sensor circuit has lower electrical resistance than expected, which usually points to a shorted heater element or damaged wiring. The code is stored when the module's heater circuit self-test sees current flow that is too high for the commanded voltage, indicating the heater is drawing excessive current.

SystemPowertrain
Code typeJaguar specific
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering

Symptoms you may notice

  • Illuminated check engine light, often with no other noticeable symptoms
  • Slightly rough idle or poor fuel economy if the sensor stays cold and the engine runs in open loop longer than normal
  • Intermittent hesitation during light acceleration when the heater circuit is failing intermittently
  • A pending P1190 that reappears after clearing, especially in cold weather when the heater is commanded on
  • No driveability complaint at all in many cases because the heater fault does not always disable the sensor signal

Common causes, most likely first

  1. Failed oxygen sensor heater element with internal shorting, which is the most common cause on higher-mileage Jaguars
  2. Chafed or pinched heater circuit wiring shorting to ground or to another wire in the harness
  3. Corroded or water-contaminated connector pins at the oxygen sensor or at the engine control module
  4. Engine control module heater driver circuit fault, though this is far less common than sensor or wiring failure
  5. Aftermarket oxygen sensor with incorrect heater resistance fitted during a previous repair
  6. Moisture ingress into the sensor connector causing a low-resistance path across the heater pins

How to diagnose and fix it

  1. Read all stored and pending codes with a scan tool that supports Jaguar-specific data, and record freeze-frame information before clearing anything
  2. Inspect the oxygen sensor connector and the harness run for chafing, corrosion, or moisture, and repair any damaged wiring first
  3. Measure the heater element resistance at the sensor connector with a multimeter and compare it to the Jaguar specification for that sensor
  4. Check the heater circuit for a short to ground or short to voltage with the sensor disconnected and the key on
  5. If resistance is out of specification, replace the affected oxygen sensor with a correct-resistance unit and clear the code
  6. If the sensor and wiring test good, check the engine control module heater driver output with a scope or bidirectional scan tool before condemning the module
  7. After repair, run the heater circuit monitor to completion and verify the code does not return over a full cold-start drive cycle

What a low-resistance heater code really means

  • A low-resistance heater fault is not the same as an open heater circuit, so replacing the sensor blindly without measuring resistance can waste money if the real problem is a chafed harness shorting to ground.
  • Jaguar oxygen sensor heaters are commanded on aggressively after a cold start, so a marginal short often only sets the code in cold weather or on the first start of the day rather than during a warm recheck.
  • Water ingress into the sensor connector is a frequent hidden cause on Jaguars with underbody splash shields missing or damaged, and the connector can look fine until the pins are inspected closely.
  • An aftermarket oxygen sensor with the wrong heater resistance will set this code repeatedly even though the sensor is new, so always verify the replacement part matches the original resistance specification.
  • This code can appear alongside mixture codes if the sensor heater fault keeps the sensor from reaching operating temperature, so diagnose the heater circuit before chasing fuel trim problems.

Can I keep driving with P1190?

You can usually keep driving short distances because the engine will still run, but avoid long periods of idling and cold-weather short trips until the fault is repaired. Prolonged driving with a shorted heater circuit can damage the engine control module driver, so have it diagnosed promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Jaguar vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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