Error Code P1195 is defined as Heated Oxygen Sensor Bank 1 Sensor 1 Slow Response. This code refers to a problem with the oxygen sensor bank 1 sensor 1, with it being slow during catalyst monitoring.

This code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II system, especially those made since 1996 up to present. Specifications on the definition, troubleshooting, and repairs of course, vary from one make and/or model to another.


Error Code P1195 is set when the oxygen sensor signal voltage is switching from lower than 0.39V to more than 0.6V and back fewer times than required, or the O2 sensor has slow response during testing period.

When this code appears, as the engine is run the coolant is more than 170˚ F, open throttle, steady to slightly increasing vehicle speed of more than 18MPH or less than 55MPH. There is light load on the engine for period no less than five minutes.

Common Symptoms

As with other error codes, this code activates the Check Engine light as its primary symptom. It can also increase fuel consumption.

Possible Causes

There are multiple factors that contribute to this code to appear, some of the possible causes are:

  • Open Bank 1 Sensor 1 O2 sensor ground circuit
  • Observable defect on Bank 1 Sensor 1 O2 sensor connector
  • Defective Bank 1 Sensor 1 O2 sensor
  • Engine fluid consumption
  • Leaking in the exhaust system
  • Defective or fault in PCM connector

How to Check

Diagnosis for this error code starts with the Bank 1 Sensor 1 Oxygen sensor, it must be working properly.  Also, the connector must be connected tightly.

Next, the exhaust system must be checked for leaks.

If everything seems okay, then the PCM must be checked or update its program.

How to Fix

The first few things technicians usually check for this error code are with the vacuum lines. Though there are many factors that may cause this code, such as malfunctioning MAP sensor solenoid. The vacuum lines must be thoroughly checked for leaks, especially for the FPS solenoid.

Other repair steps include:

Open Bank 1 Sensor 1 oxygen sensor ground circuit must be repaired, if not replaced.

Repair or replace leaking exhaust system

Repair or replace defective Bank 1 Sensor 1 oxygen sensor.

Replace PCM and/or PCM connector.

There are also times that the problem is not in the Oxygen sensor, but with the “slow” code it usually is.