How to Solve ISUZU Truck ECM Lost Communication with IDSS Diagnostic Adapter

This instruction show you guide on how to solve IDSS diagnostic adapter lost communication to ISUZU truck ECM with with Radar Sensor/ Stereo Camera.

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Procedures:

1 Scan tool power-up check

1) Connect the scan tool. Does the scan tool power up?

Yes

=>Go to Scan tool communication verification.

Go to Scan tool does not power up.

Refer to “51.Engine Control 1A.Troubleshooting(4JJ3 with DPD) Scan tool does not power up”.

2 Scan tool communication verification

1) Connect the scan tool.

2) Turn ON the ignition switch.

3) Check the communication status with the ECM using the scan tool. Can communication with the ECM be established?

Yes

Go to Intermittent conditions of engine.

Refer to “202.Engine 15D.Symptom(4JJ3 with DPD) intermittent conditions of engine”.

=>Go to Central gateway control unit communication verification.

3 Central gateway control unit communication verification

1) Verify that communication can be established with the central gateway control unit using a scan tool. Can communication with the central gateway control unit be established?

Yes

=>Go to Powertrain CAN communication circuit communication verification.

Go to Lost communication with the central gateway control unit.

Refer to “64.Body Control 10I.Troubleshooting(Central GateWay) lost communication with the central gateway control unit”.

4 Powertrain CAN communication circuit communication verification

1) Verify that communication can be established with the following control modules using a scan tool. Can communication with all the control modules be established?

Battery sensor
TCCM
Rear differential lock control unit
TCM
Information module

Yes

=>Go to ECM harness connector inspection.

Go to Powertrain CAN communication circuit inspection.

Refer to “64.Body Control 10I.Troubleshooting(Central GateWay) powertrain CAN communication circuit inspection”.

5 ECM harness connector inspection

1) Inspect for poor connections at the ECM harness connectors (C8, C9). Is the connection status normal?

Refer to “RHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to “LHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to Fuse inspection.

Repair the connections as necessary.

=>Go to Repair verification.

6 Fuse inspection

1) Inspect the following fuses for a blowout. Is the result normal?

ECM 40A slow blow fuse
ENGINE(IG1) 5A fuse

Yes

=>Go to Inspection for open circuit in ignition power supply circuit.

Replace the fuse as necessary. If the fuse blows out again, repair the short to ground in the circuit relating to each fuse.

=>Go to Repair verification.

7 Inspection for open circuit in ignition power supply circuit

1) Turn OFF the ignition switch.

2) Disconnect the ECM harness connector (C9).

3) Connect a test lamp between the ignition power supply circuit (pin 1 of C9) and the body ground.

Refer to “RHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to “LHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

4) Turn ON the ignition switch. Does the test lamp illuminate?

Yes

=>Go to ECM ground inspection.

Repair the open circuit in the ignition power supply circuit between the ENGINE(IG1) 5A fuse and the ECM (pin 1 of C9).

=>Go to Repair verification.

8 ECM ground inspection

1) Inspect the ECM ground section for corrosion or improper installation. Is the result normal?

Caution:

An open circuit in the ECM ground circuit does not cause poor communication.

Yes

=>Go to ECM main relay inspection.

Repair the ground point as necessary.

=>Go to Repair verification.

9 ECM main relay inspection

1) Turn OFF the ignition switch.

2) Connect the ECM harness connector (C9).

Refer to “RHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to “LHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

3) Replace the ECM main relay with a known good relay.

4) Turn ON the ignition switch.

5) Check the communication status with the ECM using the scan tool. Can communication with the ECM be established?

Yes

Replace the ECM main relay

=>Go to Repair verification.

=>Go to Inspection for open circuit in ECM main relay voltage supply circuit.

10 Inspection for open circuit in ECM main relay voltage supply circuit

1) Turn OFF the ignition switch.

2) Remove the ECM main relay.

3) Connect a test lamp between the ECM main relay voltage supply circuit (pin 1 of Fuse and Relay Box (Engine Compartment) ECM MAIN) and the body ground.

4) Connect a test lamp between the ECM main relay control circuit (pin 3 of Fuse and Relay Box (Engine Compartment) ECM MAIN) and the body ground.

Refer to “RHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to “LHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

5) Turn ON the ignition switch. Do both the test lamps illuminate?

Yes

=>Go to Inspection for open circuit in ECM main relay circuit.

Repair the circuit as necessary.

=>Go to Repair verification.

11 Inspection for open circuit in ECM main relay circuit

1) Install the ECM main relay.

2) While checking the operation sounds of the ECM main relay, turn the ignition switch ON/OFF. Is an operation sound of the ECM main relay heard?

Note:

The ECM main relay does not turn OFF unless a predetermined length of time has passed after turning OFF the ignition switch.

Yes

=>Go to Inspection for open circuit in ECM main relay power supply circuit.

=>Go to Inspection for open circuit in ECM main relay ground circuit.

12 Inspection for open circuit in ECM main relay ground circuit

1) Inspect the ground circuit between the ECM main relay (pin 4 of Fuse and Relay Box (Engine Compartment) ECM MAIN) and the ground terminal for the following. Is the result normal?

Open circuit
High resistance and poor connections at the ECM main relay or ground terminal

Refer to “RHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to “LHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to Inspection for open circuit in ECM main relay power supply circuit.

Repair the circuit as necessary.

=>Go to Repair verification.

13 Inspection for open circuit in ECM main relay power supply circuit

1) Inspect the battery power supply circuit between the ECM (pins 2, 3, 4, 5 and 6 of C9) and the ECM main relay (pin 2 of Fuse and Relay Box (Engine Compartment) ECM MAIN) for the following. Is the result normal?

Open circuit
High resistance or a poor connection at the ECM or ECM main relay

Refer to “RHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to “LHD Engine Control (4JJ3 with DPD)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to CAN circuit resistance check.

Repair the circuit as necessary.

=>Go to Repair verification.

14 CAN circuit resistance check

1) Connect the ECM harness connector (C9).

2) Turn OFF the ignition switch.

3) Disconnect the scan tool from the DLC (C19) if connected.

4) Measure the resistance between the CAN High circuit and the CAN Low circuit (pins 14 and 16 of C9) from the backside of the ECM harness connector with a DMM. Is the resistance within the specified range?

Note:

The parallel resistance of the 120 Ω resistor in the ECM and the 120 Ω resistor in the central gateway control unit is 60 Ω.

Refer to “RHD Controller Area Network (Central Gateway C/U (4JJ3 with DPD))” in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to “LHD Controller Area Network (Central Gateway C/U)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Value: 50 to 70 Ω

Yes

=>Go to Inspection for short circuit in CAN circuit.

=>Go to Central gateway control unit internal resistance inspection.

15 Central gateway control unit internal resistance inspection

1) Disconnect the ECM harness connector (C9).

2) Measure the resistance of the ECM harness connector (pins 14 and 16 of C9) with a DMM. Is the resistance within the specified range?

Refer to “RHD Controller Area Network (Central Gateway C/U (4JJ3 with DPD))” in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to “LHD Controller Area Network (Central Gateway C/U)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Value: 110 to 130 Ω

Yes

=>Go to ECM internal resistance inspection.

=>Go to Central gateway control unit replacement.

16 ECM internal resistance inspection

1) Disconnect the central gateway control unit harness connector (B41).

2) Measure the resistance of the central gateway control unit harness connector (pins 5 and 6 of B41) with a DMM. Is the resistance within the specified range?

Refer to “RHD Controller Area Network (Central Gateway C/U (4JJ3 with DPD))” in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to “LHD Controller Area Network (Central Gateway C/U)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Value: 110 to 130 Ω

Yes

=>Go to Inspection for open circuit and short circuit in CAN circuit.

=>Go to ECM replacement.

17 Inspection for open circuit and short circuit in CAN circuit

1) Inspect for poor connections at the ECM harness connector (pins 14 and 16 of C9). Is the connection status normal?

2) Inspect the CAN High circuit and the CAN Low circuit between the central gateway control unit (pins 5 and 6 of C41) and the ECM (pins 14 and 16 of C9) for the following. Is the result normal?

Open circuit
Short together
High resistance

Refer to “RHD Controller Area Network (Central Gateway C/U (4JJ3 with DPD))” in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to “LHD Controller Area Network (Central Gateway C/U)” in the ETM (wiring diagram). (Open using the ETM viewer.).

3) Are all of the results normal?

Yes

=>Go to ECM replacement.

Repair the circuit as necessary.

=>Go to Repair verification.

18 Inspection for short circuit in CAN circuit

1) Inspect the CAN High circuit and the CAN Low circuit between the central gateway control unit (pins 5 and 6 of C41) and the ECM (pins 14 and 16 of C9) for the following. Is the result normal?

Short to ground
Short to the battery power supply circuit or short to the ignition power supply circuit

Refer to “RHD Controller Area Network (Central Gateway C/U (4JJ3 with DPD))” in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to “LHD Controller Area Network (Central Gateway C/U)” in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to ECM replacement.

Repair the circuit as necessary.

=>Go to Repair verification.

19 Central gateway control unit replacement

Note:

Perform programming after replacing the central gateway control unit.

Refer to “9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control central gateway control unit removal”.

Refer to “9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control central gateway control unit installation”.

Refer to “9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control central gateway control unit setting”.

Procedure completion

=>Go to Repair verification.

20 ECM replacement

Note:

Perform programming after replacing the ECM.

Refer to “1.Engine 1Z.Engine Electrical Control(4JJ3 with DPD) ECM removal”.

Refer to “1.Engine 1Z.Engine Electrical Control(4JJ3 with DPD) ECM installation”.

Refer to “1.Engine 1Z.Engine Electrical Control(4JJ3 with DPD) ECM setting”.

Procedure completion

=>Go to Repair verification.

21 Repair verification

1) Turn OFF the ignition switch.

2) Reconnect all of the removed fuses, relays, and harness connectors.

3) Turn ON the ignition switch.

4) Check the communication status with the ECM using the scan tool. Can communication with the ECM be established?

Yes

The system is normal.

=>Go to Central gateway control unit communication verification.

For more guide about ISUZU,please refer to:ISUZU Trouble Repair.

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