Primary Heated Oxygen Sensor (Primary H02S) (Sensor 1) - Honda CR-V 1997 Service Manual

PGM-FI System
Primary Heated Oxygen Sensor (Primary H02S) (Sensor 1)
The Heated Oxygen Sensors (H02S) detect the oxygen content in the exhaust gas and signal the ECM/PCM. In operation,
the ECM/PCM receives the signals from the sensor and varies the duration during which fuel is injected. To stabilize the
sensor's output, the sensor has an internal heater. The Primary H02S (Sensor 1) is installed in exhaust pipe A.
H02S:
SENSOR
TERMINALS
HEATER
TERMINALS
VOLTAGE IVI
_ _ _ - "
STOICHIOMETRIC
,fIR-FUEL RATIO
1-- - -1---
RICH - AtR· - LEAN
FUEL
RATIO
I
P0131
I
The scan tool indicates Diagnostic Trouble Code (OTC) P0131:
A
low voltage problem in the Primary Heated
Oxygen Sensor (H02S) (Sensor 1) circuit.
'97 - 98 models:
- The MIL has been reported on.
- OTC P0131 is stored.
I
Pro~.m verification:
1. Do the ECM/PCM Reset Pro-
cedure.
2. Start the engine . Hold the
engine at 3,000 rpm with no
load (in Park or neutral) until
the rad iator fan comes on.
3. Test-drive with the AfT in
~
position (Mrr in 4th gear)
••
Check
the
Primary H02S
(Sensor 1) output voltage with
the scan tool during accelera-
tion using wide open throttle.
I
Intermittent failure, system is OK
Does the voltage stay at
0.1 V
NO
at this time. Check for poor eon-
or less?
nactions or loose wires at C111
(Primary H02S, Sensor 11 and at
I
YES
the ECM/PCM.
Check the fuel pfessure
(s~
page
11·178).
I
'-..
NO
Is it normal?
/'
Repair the fuel supply system.
I
YES
(To page 11 -111)
11-110