LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Saturn >> 2000 >> LS Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0134: O2S Circuit - Insufficient Activity - Sensor 1 >> Diagnostic Procedures
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Operate engine at 1500 RPM for several minutes. Ensure engine coolant temperature is greater than 158°F (70°C). Using scan tool, monitor O2S1 voltage. If voltage reading is 399-499 mV, go to next step. If voltage reading is not 399-499 mV, problem is intermittent. See DIAGNOSTIC AIDS .
  3. Disconnect O2S1 harness connector. Using a jumper wire, jumper O2S1 harness connector terminal "B" (Purple wire) to ground. Observe scan tool reading. If voltage reading is less than 50 mV, go to next step. If voltage reading is not less than 50 mV, check for open in circuit or terminal tightness. Repair as necessary. If circuit or terminals are okay, replace PCM.
  4. Disconnect jumper from ground. Connect jumper between O2S1 harness connectors "A" (Tan wire) and "B" (Purple wire). Observe scan tool reading. If voltage reading is not less than 50 mV, go to next step. If voltage is less than 50 mV, check for terminal tightness. Repair as necessary. If terminals are okay, replace O2S1 sensor.
  5. Check for terminal tightness or open in circuit between O2S1 harness connector terminal "A" (Tan wire) and PCM. Repair as necessary. If circuit or terminals are okay, replace PCM.
scientia non olet · About LEMON Manuals