P0134

Description
HO2S 1 CIRCUIT INSUFFICIENT ACTIVITY

PCM provides about 0.45 volt reference to HO2S 1. HO2S 1
sensor signal voltage varies from about one volt when exhaust is rich
to about 0.1 volt when exhaust is lean. PCM reads and stores sensor
voltage information and evaluates the voltage samples to determine
amount of time sensor voltage is out of range. If HO2S 1 voltage is
out of predetermined range, DTC will set.

Symptoms

• Check engine light illumination
• Poorly running/engine missing
• Blowing black smoke
• Poor fuel economy
• stalling, stuttering

Causes

• Bad O2 (oxygen) sensor
• Bad heater circuit in the O2 sensor
• Wiring or connector to the sensor damaged.
• Blown heater circuit fuse
• Holes in the exhaust system
• PCM failure

Possible Solutions

• Replace the oxygen sensor
• Rusted exhaust pipe, repair.
• Inspect wiring & connector(*) for problems, repair.
• Excessive amperage blowing heater fuse (replace sensor and blown fuse)
• Replace PCM (last resort)