DTC P0131

DTC P0131  : A/F Sensor (Sensor 1) Circuit Low Voltage

NOTE:  Before you troubleshoot, review the general troubleshooting information .

DTC (PGM-FI)

1. Problem verification

   -1. Turn the vehicle to the ON mode.

   -2. Clear the DTC with the HDS.

   -3. Start the engine.

   -4. Hold the engine speed at 3, 000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.

   -5. Check for Pending or Confirmed DTCs with the HDS.

   DTC Description	Confirmed DTC	Pending DTC
   P0131 A/F Sensor (Sensor 1) Circuit Low Voltage

   Is DTC P0131 indicated?

   YES 

   The failure is duplicated. Go to step 2.

   NO 

   Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the PCM. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot .

2. A/F sensor (Sensor 1) internal circuit check

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Disconnect the following connector.

   A/F sensor (Sensor 1) 6P connector

   -3. At the A/F sensor (Sensor 1) side, check for continuity between the following test points and body ground individually.

   Test condition	Vehicle OFF (LOCK) mode
   	A/F sensor (Sensor 1) 6P connector: disconnected

   Connector	Terminal
   A/F sensor (Sensor 1) 6P connector (male terminals) (sensor side):	No. 1
   	No. 3
   	No. 4
   	No. 6

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity at any terminal?

   YES 

   Replace the A/F sensor (Sensor 1) .

   NO 

   Go to step 3.

3. Shorted wire check (LAF lines)

   -1. Jump the SCS line with the HDS, and wait more than 1 minute.

   -2. Disconnect the following connector.

   PCM connector No. 1 (96P)

   -3. Check for continuity between the following test points and body ground individually.

   Test condition	Vehicle OFF (LOCK) mode
   	A/F sensor (Sensor 1) 6P connector: disconnected
   	PCM connector No. 1 (96P): disconnected

   Connector	Terminal
   A/F sensor (Sensor 1) 6P connector (female terminals):	No. 1
   	No. 3
   	No. 4
   	No. 6

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity at any terminal?

   YES 

   Repair a short in the wire (s) between PCM connector No. 1 terminals No. 54 (LAF VN wire), No. 36 (LAF VG wire), No. 55 (LAF CA wire), and/or No. 37 (LAF CP wire) and the A/F sensor (Sensor 1).

   NO 

   Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM , then recheck. If DTC P0131 goes away and the PCM was substituted, replace the original PCM .