How to Repair PACCAR Truck Payrometer Gauge Inoperative Trouble

This instruction show you guide on how to repair Paccar truck DTC17303 and DTC17304 pyrometer gauge inoperative trouble.More topics about Paccar truck,please refer to:PACCAR Truck Repair.

 

Preparations:

Paccar ESA Electronic Service Analyst v5.4.3 v5.2.2 Free Download

 

Procedures:

Symptom: Pyrometer gauge inoperative. All other gauges are operational.

The Pyrometer Gauge uses a thermocouple sensor to measure engine exhaust gas temperature after it leaves the turbo.

The following procedures have been developed to assist the technician in diagnosing multiplexed instrumentation problems using the ElectronicService Analyst (ESA) hardware/software diagnostic tool. It is assumed the service technician performing instrumentation repairs is knowledgeable about how to use ESA.

Repair-PACCAR-Truck-Payrometer-Gauge-Inoperative-Trouble-1

 

Step 1:

Turn ignition key ON.

Start PACCAR ESA, then select“Connect” to establish communication to the vehicle.

 

Step 2:

Select “Monitor.”From the “Components”window, select “Exhaust

Temperature,” then select “Open.

 

Gauge graphic on screen displays reasonable readin Go to Step 3.

Gauge graphic on screen does not display reasonable reading. Go to Step 4

 

Step 3:

Select “Simulate”. Drag the “Value” bar until the pointer on the gauge image is approximately

mid-scale. Observe vehicle gauge movement

 

Vehicle gauge does not move. Go to Step 3-1.

Vehicle gauge reading is in the same range as the ESA gauge image. Go to Step 3-7.

 

Perform the following checks:

1.Check CVSG data link wiring: Observe Gauge position in the wiring daisy chain.

2.If gauge is mounted between two other functioning gauges CVSG data link wiring is OK. go to Step 3-5

If gauge is last gauge in daisy chain or followed by other non-functional gauges, go to Step 3-2.

b.Check continuity between Pin 1 on gauge harness connector and

Pin 14 of the 52 Pin ICU connector C.

3.Check continuity between Pin 3 on gauge harness connector and Pin 15 of the 52 Pin ICU connector C.

4.Repair daisy chain jumper harness as necessary.

5.Once continuity on both wires exists, perform “Simulate” test again.

a.If gauge functions properly during “Simulate” test, repair is complete.

Return truck to service.

b.If gauge does not function during “Simulate” test, install Test ICU and perform “Simulate” test again.

i.If gauge functions properly test is complete. Install new ICU permanently. Re-test and return truck to service.

ii.If gauge does not function properly during “Simulate” test,replace gauge.

 

6.Once gauge is replaced.

a.Verify gauge functionality.

b.Return truck to service.

7.Is this a recheck after Step 5, Step 6 or Step 7?

a.Yes. Return truck to service.

b.No, Gauge and CVSG data link wiring is not the problem. Go to Step 4

 

Step 4:

Select “Diagnose” to view “Active” ammeter diagnostic trouble codes.

DTC 17303 displayed – Open in exhaust temp circuit.

Indicates the problem could be an open in the wiring from the ICU to the pyrometer sensor or a defective sensor. Go to Step 5, and if necessary,Step 6

 

DTC 17304 displayed – Short in exhaust temp circuit.

Indicates the problem could be a short to ground in the wiring from the ICU to the pyrometer sensor or a defective sensor. Go to Step 5, and if necessary,Step 7.

 

Step 5:

Unplug pyrometer harness connector at sensor.

Using a digital multimeter, check continuity on ground and signal wire at sensor connector.

Pin 1 – Ground

Pin 2 – Signal

See Harness Interface

Diagrams for possible sensor locations.

See Connector

Identification for position and identification of the electrical connectors of ICU/CECU.

See ICU/CECU Pinout for terminal details of the ICU/CECU electrical connection

 

Sensor Ground) – There should be continuity between the sensor connector ground wire (Pin 1) and a cab ground terminal.

(Signal) – There should be continuity between the sensor connector signal wire (Pin 2) and

Pin 23 of the 52 Pin ICU connector C.

 

Check for continuity between sensor connector Pin 1 and a cab ground terminal.

a.If there is continuity between Pin 1 and the ground terminal, test is complete. Go to Step 5-2.

b.If there is no continuity between Pin 1 and the ground terminal, repair wiring as necessary. Go to Step 5-1.

2.Check for continuity between sensor connector Pin 2 and Pin 23 of the 52 Pin ICU connector C.

a.If there is continuity between Pin 2 and Pin 23, test is complete.Go to Step 6.

b.If there is no continuity between Pin 2 and Pin 23 at ICU, repair wiring as necessary. Go to Step 5-2.

Alternate test method: Resistance in the pyrometer sensor (thermocouple) signal wire changes as exhaust temperature increases/decreases.

1.By unplugging the pyrometer sensor harness connector and connecting a resistor decade box (i.e.Ametek PST2000 Tester), or an appropriate resistor to Pins 1 and 2, you can simulate the sensor by dialing in a known resistance.

2.Observe vehicle gauge reading on dash.

3.If gauge needle moves to approximately the same temperature as in the table below, the problem is a defective pyrometer sensor. See Table below

Repair-PACCAR-Truck-Payrometer-Gauge-Inoperative-Trouble-2

 

Step 6:

Select “Diagnose” to view exhaust temperature gauge DTCs.

Unplug pyrometer harness connector at sensor.

See Harness Interface

Diagrams for possible sensor locations.

See Connector

Identification for position and identification of the electrical connectors of ICU/CECU.

See ICU/CECU Pinout for terminal details of the ICU/CECU electrical connection

 

DTC 17303 – Open in exhaust temp circuit is displayed as“Active.”

1.Using a jumper wire, jump across sensor harness connector Pins 1 and 2

Repair-PACCAR-Truck-Payrometer-Gauge-Inoperative-Trouble-3

Pin 1

Pin 2

a.If an “Active” DTC 17304 – Short in exhaust temp circuit is now displayed, you have confirmed there is not an open in the sensor signal wire to the ICU. The original fault (DTC 17303) was logged because there is an open in the pyrometer sensor itself, not the wiring. Replace sensor.

b.If DTC 17304 is not displayed, there is an open circuit in the signal wire between sensor connector Pin 2 and Pin 23 of the 52 Pin ICU connector C. Repair wiring as necessary.

Alternate test method: Check for continuity between sensor connector Pin 2 (sensor signal) and Pin 23 of the 52 Pin ICU connector C.

1.If there is no continuity, repair wiring as necessary. After repairs, DTC 17303 should now be displayed as “Inactive.”

2.If there is continuity between sensor connector Pin 2 and Pin 23 of the 52 Pin ICU connector C, the open circuit is in the sensor itself, not in the wiring. Replace sensor

 

Step 7:

Select “Diagnose”to view exhaust temperature gauge DTCs.

Next, unplug the pyrometer harness connector at sensor.

See Harness Interface

Diagrams for possible sensor locations.

See Connector

Identification for position and identification of the electrical connectors of ICU/CECU.

See ICU/CECU Pinout for terminal details of he ICU/CECU electrical connection

 

DTC 17304 – Short in exhaust temp circuit is displayed as“Active.”

If the fault is still “Active” after unplugging the sensor connector, you have confirmed there is a short to ground between Pin 2 (sensor signal) and Pin 23 of the 52 Pin ICU connector C.

1.Check for a pinched or chaffed wire between Pin 2 (sensor signal) and

Pin 23 of the 52 Pin ICU connector C. Repair wiring as necessary. Go to Step 2

 

DTC 17304 – Short in exhaust temp circuit is now displayed as“Inactive.”

If DTC 17304 changes to “Inactive” after unplugging the sensor connector, you have confirmed the problem is a short in the sensor itself, not the wiring.

Replace sensor. Go to Step 2.

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