P1271 Isuzu Cylinder #1 High To Low Side Open

P1271 Isuzu Cylinder #1 High To Low Side Open

Possible causes
  • Harness or connectors (The A/F sensor 1 circuit is open or shorted.)
  • Air fuel ratio (A/F) sensor 1
  • What about the obd code?
  • The A/F signal computed by ECM from the A/F sensor 1 (Bank 1) signal is constantly approx. 0V.
  • Symptoms
    – Engine Light ON (or Service Engine Soon Warning Light)
    P1271 Isuzu Description

    The A/F sensor is a planar dual-cell limit current sensor. The sensor element of the A/F sensor is the combination of a Nernst concentration cell (sensor cell) with an oxygen-pump cell, which transports ions. It has a heater in the element.

    The sensor is capable of precise measurement λ= 1, but also in the lean and rich range. Together with its control electronics, the sensor outputs a clear, continuous signal throughout a wide λ range (0.7 < λ < air).

    The exhaust gas components diffuse through the diffusion gap at the electrode of the oxygen pump and Nernst concentration cell, where they are brought to thermodynamic balance.

    An electronic circuit controls the pump current through the oxygen-pump cell so that the composition of the exhaust gas in the diffusion gap remains constant at λ = 1. Therefore, the A/F sensor is able to indicate air/fuel ratio by this pumping of current. In addition, a heater is integrated in the sensor to ensure the required operating temperature of 700 – 800C (1,292 – 1,472F).

    P1271 Isuzu Information for specific makes
    Isuzu Vehicle:2013 Isuzu,2012 Isuzu,2011 Isuzu,2010 Isuzu,2009 Isuzu,2008 Isuzu,2007 Isuzu,2006 Isuzu,2005 Isuzu,2004 Isuzu,2003 Isuzu,2002 Isuzu,2001 Isuzu,2000 Isuzu,1999 Isuzu,1998 Isuzu,1997 Isuzu,1996 Isuzu,Isuzu Rodeo,Isuzu Trooper,Isuzu Ascender
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