31637-ZY3-000 Honda STAY, ALTERNATOR (Honda Code 6991533).

Table 1
Diagnostic Codes Table
Code and Description Conditions which Generate this Code System Response Label on Sensor
173–3 Engine Exhaust Gas Temperature : Voltage Above Norma The Electronic Control Module (ECM) detects a signal voltage that is above normal. The code is logged.
The ECM flags the exhaust temperature as invalid data. "FRONT LEFT EXHAUST TC"
Located in the exhaust manifold below the turbocharger
173-4 Engine Exhaust Gas Temperature : Voltage Below Normal The Electronic Control Module (ECM) detects a signal voltage that is below normal.
173-8 Engine Exhaust Gas Temperature : Abnormal Frequency pulse width or period The Electronic Control Module (ECM) detects a sensor frequency that is greater than 600 Hz or less than 400 Hz.
The ECM detects a duty cycle that is greater than 88 percent or a duty cycle that is less than 22 percent. System OperationA Pulse Width Modulated Sensor (PWM) provides a signal to the Electronic Control Module (ECM) from the exhaust temperature sensor. The sensor receives a 8.0 0.4 VDC regulated voltage from the ECM.The sensor generates a PWM signal that is in a specific range of duty cycle that is sent to the ECM. This range is directly related to the temperature that is sampled by the temperature probe. When the temperature of the sensor probe is 50 °C (122 °F) the duty cycle output of the sensor is 22 percent. When the temperature of the sensor probe is 850 °C (1550 °F) the duty cycle output of the sensor is 88 percent. As the temperature of the probe fluctuates between the minimum and the maximum temperatures, the duty cycle fluctuates on a scale that is directly related to the temperature of the temperature probe.The ECM performs an automatic calibration of this sensor whenever the ECM is powered and the engine has been off for at least five seconds.The ECM provides short circuit protection for the internal power supply. A short circuit to the battery will not damage the internal power supply of the ECM.
Illustration 1 g06204112
Schematic of the sensor circuit for the PWM sensors
Illustration 2 g06204117
(1) Exhaust Temperature Sensor ConnectionTest Step 1. Inspect the Electrical Connectors and the Wiring
Illustration 3 g01406077
Location of the ECM connector that is for the exhaust temperature sensors
(3) J2/P2 ECM connectors
Thoroughly inspect connectors (1), (2) and (3). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details that are related to inspection of the electrical connectors.
Illustration 4 g06204128
ECM Side
(4) P2-14 Exhaust Temperature Sensor Return/Ground
(5) P2-29 Exhaust Temperature Sensor Supply
(6) P2-73 Exhaust Temperature Sensor Signal
Illustration 5 g06204137
Terminal locations at the P2 ECM connector that are for the exhaust temperature sensor
(P2-29) Exhaust Temperature Sensor Supply
(P2-73) Exhaust Temperature Sensor Signal
(P2-14) Exhaust Temperature Sensor Return/Ground
Illustration 6 g01159881
Terminal locations at the connectors for the exhaust temperature sensor
(Terminal A) Digital sensor supply
(Terminal B) Digital return
(Terminal C) Exhaust temperature
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the customer connector that are associated with the circuit.
Check the allen head screw on each ECM connector for the proper torque. refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasion and for pinch points.Expected Result:
All connectors, pins, and sockets are coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK- The connectors and wiring appear to be OK. Proceed to Test Step 2.
Not OK- The connectors and/or wiring are not OK.Repair: Repair the connectors or wiring and/or replace the connectors or wiring.STOPTest Step 2. Check the Supply Voltage at the Sensor
A. Disconnect the exhaust temperature sensor at the harness connector.B. Restore electrical power to the ECM. Turn the keyswitch to the ON position.C. Measure the voltage across terminal A (digital sensor supply) and terminal B (digital return) on the harness side of the connector.D. Remove electrical power from the ECM. Turn the keyswitch to the OFF position.E. Restore the wiring to the original configuration.Expected Result:
The supply voltage measures 8.0 0.4 VDC at the sensor connector.Results:
OK- The correct supply voltage is measured at the sensor connector. The sensor is receiving the correct supply voltage. Proceed to Test Step 3.
Not OK- The voltage is not correct at the sensor connector.Repair: There is a problem in the circuit for the digital sensor supply that is between the ECM and the exhaust temperature sensor. Repair the circuit. Refer to Troubleshooting, "Digital Sensor Supply Circuit - Test" for details that are related to troubleshooting a problem with the circuit.STOPTest Step