heating ISUZU KB P190 2007 Workshop User Guide
[x] Cancel search | Manufacturer: ISUZU, Model Year: 2007, Model line: KB P190, Model: ISUZU KB P190 2007Pages: 6020, PDF Size: 70.23 MB
Page 1213 of 6020
Engine Control System (4JH1) 6E-179
DTC P0645 (Symptom Code 8) (Flash Code 46)
Circuit Description
The engine control module (ECM) controls the ai
r
conditioning (A/C) compressor relay, which supplies
power to the A/C compressor clutch based on A/C
request input to the ECM from the heating, ventilation
and air conditioning (HVAC) controls. The ECM
commands the A/C compressor relay ON at engine run.
If the ECM detects a short to battery or ignition voltage
on the A/C compressor relay control circuit, this DTC
will set.
Condition for Running the DTC
• The ignition switch is ON.
• The A/C compressor relay is once commanded
ON.
Condition for Setting the DTC • The ECM detects a high voltage condition on the
A/C compressor relay control circuit for longer than
3 seconds when the relay is commanded ON.
Action Taken When the DTC Sets • The ECM illuminates the malfunction indicato
r
lamp (MIL) when the diagnostic runs and fails.
Condition for Clearing the MIL/DTC
• The ECM turns OFF the MIL when the diagnostic
runs and does not fail.
• A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Diagnostic Aids • If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
Notice: • The A/C compressor relay is commanded OFF
when the engine coolant temperature is reached
around 105°C (221°F) and it commanded ON
again below 100°C (212°F).
DTC P0645 (Symptom Code 8) (Flash Code 46)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views
Step Action Value(s) Yes No
1 Did you perform the Diagnostic System Check-
Engine Controls?
Go to Step 2 Go to Diagnostic
System Check-
Engine Controls
2 1. Install the scan tool. 2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Turn ON the blower motor switch and the A/C compressor switch.
5. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool when the A/C
Relay Command parameter is ON.
Does the DTC fail this ignition?
Go to Step 3 Go to Diagnostic
Aids
3 1. Turn OFF the ignition. 2. Replace the A/C compressor relay with the tail relay or replace with a known good relay.
3. Start the engine.
4. Turn ON the blower motor switch and the A/C compressor switch.
5. Monitor the DTC Information with the scan tool when the A/C Relay Command parameter is ON.
Does the DTC fail this ignition?
Go to Step 4 Go to Step 5
4 1. Test the control circuit of the A/C compressor relay between the ECM (pin 41 of C-56
connector) and the A/C compressor relay (pin 5
of X-14 connector) for a short to battery or
ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Go to Step 7 Go to Step 6
5 Replace the A/C compressor relay. Did you complete the replacement?
Go to Step 7
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Page 1276 of 6020
6E-242 Engine Control System (4JH1)
DTC A/C Compressor System Check
Description
W hen air conditioning (A/C) and blower fan are
selected, and if the system has a sufficient refrigerant
charge. A 12-volt signal is supplied to the A/C request
input of the Engine Control Module (ECM). The A/C
request signal may be temporarily canceled during
system operation by the electronic thermostat in the
evaporator to prevent the evaporator icing. Also, it is
cancelled when the pressure switch detected abnormal
pressure in the line. W hen the A/C request signal is
received by the ECM, the ECM supplies a ground from
the A/C compressor relay if the engine operating
conditions are within acceptable ranges. W ith the A/C
compressor relay energized, voltage is supplied to the
compressor clutch coil. The ECM will enable the
compressor clutch to engage whenever A/C has been
selected with the engine running and enable conditions
are met.
Condition for Running the A/C Compressor:
• The engine is running.
• The A/C switch is ON.
• The engine coolant temperature (ECT) is less than
105 °C(221 °F).
A/C Compressor System Check
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views
Chart 1 of 2
Step Action Value(s) Yes No
1 Did you perform the Diagnostic System Check-
Engine Controls?
Go to Step 2 Go to Diagnostic
System Check – Engine Controls
2 1. Install the scan tool. 2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Monitor the Diagnostic Trouble Code (DTC) Information of the engine control system with the
scan tool and check whether following DTC(s) is
set: • P0115 (Symptom Code 1 & 2)
• P0645 (Symptom Code 4 & 8)
Are any of the above DTC(s) set?
Refer to Applicable DTC Go to Step 3
3 1. Turn ON the ignition, with the engine OFF.
2. Turn ON the blower motor switch.
Does the blower motor turn ON and operate
correctly?
Go to Step 4 Refer to Applicable
Diagnostic Chart in Heating & Air Conditioning Section
4 1. Turn OFF the blower motor switch. 2. Keep the A/C switch OFF.
Does the A/C Request Signal parameter indicate
OFF?
Go to Step 5 Go to Chart 2 of 2
with heater Step 1 OR
Go to Chart 2 of 2
without heater Step 1
5 1. Start the engine and let the engine idle. 2. Keep the blower motor switch OFF.
3. Keep the A/C switch OFF.
Does the A/C compressor clutch keep OFF
(disengage)?
Go to Step 6 Go to Step 11
6 1. Turn ON the blower motor switch. 2. Keep the A/C switch OFF.
Does the A/C compressor clutch keep OFF
(disengage)?
Go to Step 7 Go to Chart 2 of 2
with heater Step 7 OR
Go to Chart 2 of 2
without heater Step 4
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Page 1277 of 6020
Engine Control System (4JH1) 6E-243
Step Action Value(s) Yes No
7 1. Turn OFF the blower motor switch.
2. Turn ON the A/C switch.
Does the A/C compressor clutch keep OFF
(disengage)?
Go to Step 8 Go to Chart 2 of 2
with heater Step 8 OR
Go to Chart 2 of 2
without heater Step 10
8 1. Turn ON the blower motor switch. 2. Keep the A/C switch ON.
Does the A/C compressor clutch ON and OFF
(engage and disengage) periodically within the
Condition for Running the A/C Compressor?
Go to Step 9 Go to Step 10
9 Does the air flow cool enough.
System OK Refer to Applicable
Diagnostic Chart in Heating & Air Conditioning Section
10 Does the A/C Relay Command parameter indicate ON at previous step?
Go to Step 14 Go to Chart 2 of 2
with heater Step 9 OR
Go to Chart 2 of 2
without heater Step 11
11 1. Turn OFF the ignition. 2. Disconnect the A/C compressor clutch harness connector (E-3).
3. Start the engine.
Does the A/C compressor clutch ON (engage)?
Go to Step 22 Go to Step 12
12 1. Turn OFF the ignition. 2. Remove the A/C compressor relay from the engine room relay block.
3. Connect a test lamp between the A/C compressor clutch voltage supply circuit (pin 2 of
X-14 connector) and a known good ground.
4. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?
Go to Step 13 Go to Step 21
13 Repair the short to battery or ignition voltage on the A/C compressor voltage feed circuit between the
A/C compressor relay (pin 2 of X-14 connector) and
the A/C compressor (E-3).
Did you complete the repair?
Go to Step 23
14 1. Turn OFF the ignition.
2. Remove the A/C compressor relay from the engine room fuel block.
3. Connect a test lamp between the voltage feed circuit of the relay switch side terminal (pin 1 of
X-14 connector) and known good ground.
4. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?
Go to Step 15 Go to Step 17
15 1. Keep the ignition ON, with the engine OFF. 2. Disconnect the test lamp.
3. Connect a 3-amp fused jumper wire between both switch side terminals of the A/C compressor
relay (pins 1 and 2 of X-14 connector).
Does the A/C compressor clutch click (engage)?
Go to Step 19 Go to Step 16
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Page 1278 of 6020
6E-244 Engine Control System (4JH1)
Step Action Value(s) Yes No
16 1. Keep the ignition ON, with the engine OFF.
2. Keep 3-amp fused jumper wire with connected.
3. Disconnect A/C compressor clutch harness connector.
4. Connect a test lamp between A/C compressor voltage feed circuit (E-3) and a known good
ground.
Does the test lamp illuminate?
Go to Step 20 Go to Step 18
17 Repair the open circuit or high resistance on the relay switch side voltage feed circuit between the
A/C compressor relay (pin 1 of X-14 connector) and
the A/C (10A) fuse (EB-13).
Did you complete the repair?
Go to Step 23
18 Repair the open circuit or high resistance on the
relay switched voltage supply circuit between the
A/C compressor relay (pin 2 of X-14 connector) and
the A/C compressor clutch (pin 1 of E-3 connector).
Did you complete the repair?
Go to Step 23
19 1. Turn OFF the ignition.
2. Inspect for an intermittent and for poor connections at the A/C compressor relay
terminals (pins 3 and 5 of X-14 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 23 Go to Step 21
20 1. Turn OFF the ignition. 2. Inspect for an intermittent and for a poor connection at the harness connector of the A/C
compressor clutch (E-3).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 23 Go to Step 22
21 Replace the A/C compressor relay. Did you complete the replacement?
Go to Step 23
22 Replace the A/C compressor. Refer to Heating and
Air Conditioning section.
Did you complete the replacement?
Go to Step 23
23 1. Reconnect all previously disconnected fuse,
relay or harness connector(s).
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Turn ON the blower motor switch.
Does the blower motor turn ON and operate
correctly?
Go to Step 4 Refer to Applicable
Diagnostic Chart in Heating & Air Conditioning Section
Chart 2 of 2 with heater
Step Action Value(s) Yes No
1 1. Turn OFF the ignition.
2. Replace the thermo relay with the horn relay or replace with a known good relay.
3. Turn OFF the blower motor switch.
4. Turn OFF the A/C switch.
5. Turn ON the ignition, with the engine OFF.
Does the A/C Request Signal parameter indicate
OFF?
Go to Step 33 Go to Step 2
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Page 1282 of 6020
6E-248 Engine Control System (4JH1)
Step Action Value(s) Yes No
27 1. Turn OFF the ignition.
2. Inspect for an intermittent and for poor connections at the thermo relay terminals (pins
1, 2, 3 and 4 of X-15 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 39 Go to Step 33
28 1. Turn OFF the ignition. 2. Inspect for an intermittent and for poor connections at the harness connector of the
pressure switch (pins 1 and 2 of C-24 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 39 Go to Step 34
29 1. Turn OFF the ignition. 2. Inspect for an intermittent and for poor connections at the harness connector of the
electronic thermostat (pins 1, 2 and 3 of C-55
connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 39 Go to Step 35
30 1. Turn OFF the ignition. 2. Inspect for an intermittent and for poor connections at the harness connector of the A/C
switch (pins 1 and 5 of B-57 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 39 Go to Step 36
31 1. Turn OFF the ignition. 2. Inspect for an intermittent and for a poor connection at the harness connector of the
blower motor switch (pin 1 of B-13 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 39 Go to Step 37
32 1. Turn OFF the ignition. 2. Inspect for an intermittent and for a poor connection at the harness connector of the ECM
(pin 33 of C-56 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 39 Go to Step 38
33 Replace the thermo relay. Did you complete the replacement?
Go to Step 39
34 Replace the pressure switch. Refer to Heating and
Air Conditioning section.
Did you complete the replacement?
Go to Step 39
35 Replace the electronic thermostat. Refer to Heating
and Air Conditioning section.
Did you complete the replacement?
Go to Step 39
36 Replace the A/C switch. Refer to Heating and Air
Conditioning section.
Did you complete the replacement?
Go to Step 39
37 Replace the blower motor switch. Refer to Heating
and Air Conditioning section.
Did you complete the replacement?
Go to Step 39
38 Important: Replacement ECM must be
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement?
Go to Step 39
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Page 1283 of 6020
Engine Control System (4JH1) 6E-249
Step Action Value(s) Yes No
39 1. Reconnect all previously disconnected fuse,
relay or harness connector(s).
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Turn ON the blower motor switch.
Does the blower motor turn ON and operate
correctly?
Go to Char 1 of 2 Step 4 Refer to Applicable
Diagnostic Chart in Heating & Air Conditioning Section
Chart 2 of 2 without heater
Step Action Value(s) Yes No
1 1. Turn OFF the ignition.
2. Replace the thermo relay with the horn relay or replace with a known good relay.
3. Turn OFF the blower motor switch.
4. Turn OFF the A/C switch.
5. Turn ON the ignition, with the engine OFF.
Does the A/C Request Signal parameter indicate
OFF?
Go to Step 37 Go to Step 2
2 1. Turn OFF the ignition. 2. Remove the thermo relay from the engine room relay block.
3. Turn ON the ignition, with the engine OFF.
Does the A/C Request Signal parameter indicate
OFF?
Go to Step 3 Go to Step 5
3 1. Turn OFF the ignition. 2. Reinstall the thermo relay.
3. Remove the radiator grille in order to access the pressure switch.
4. Disconnect the pressure switch harness connector (C-24).
5. Turn OFF the blower motor switch.
6. Turn OFF the A/C switch.
7. Turn ON the ignition, with the engine OFF.
Does the A/C Request Signal parameter indicate
OFF?
Go to Step 7 Go to Step 6
4 1. Turn OFF the ignition. 2. Remove the glove box in order to access the electronic thermostat.
3. Back probe a test lamp between the electronic thermostat harness (pin 2 of C-55 connector) and
battery voltage.
4. Turn ON the blower motor switch.
5. Turn OFF the A/C switch.
6. Keep the ignition OFF.
Does the test lamp illuminate?
Go to Step 8 Go to Step 9
5 Repair the short to battery or ignition voltage on the thermo relay signal input circuit between the thermo
relay (pin 1 of X-15 connector) and the engine
control module (ECM) (pin 33 of C-56 connector).
Did you complete the repair?
Go to Step 43
6 Repair the short to ground between the thermo relay
(pin 5 of X-15 connector) and pressure switch (pin 1
of C-24 connector).
Did you complete the repair?
Go to Step 43
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Page 1287 of 6020
Engine Control System (4JH1) 6E-253
Step Action Value(s) Yes No
31 1. Turn OFF the ignition.
2. Inspect for an intermittent and for poor connections at the thermo relay terminals (pins
1, 2, 3 and 4 of X-15 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 43 Go to Step 37
32 1. Turn OFF the ignition. 2. Inspect for an intermittent and for poor connections at the harness connector of the
pressure switch (pins 1 and 2 of C-24 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 43 Go to Step 38
33 1. Turn OFF the ignition. 2. Inspect for an intermittent and for poor connections at the harness connector of the
electronic thermostat (pins 1, 2, 3 and 4 of C-55
connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 43 Go to Step 39
34 1. Turn OFF the ignition. 2. Inspect for an intermittent and for poor connections at the harness connector of the A/C
switch (pins 10 and 11 of B-57 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 43 Go to Step 40
35 1. Turn OFF the ignition. 2. Inspect for an intermittent and for a poor connection at the harness connector of the
blower motor switch (pin 1 of B-13 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 43 Go to Step 41
36 1. Turn OFF the ignition. 2. Inspect for an intermittent and for a poor connection at the harness connector of the ECM
(pin 33 of C-56 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
Go to Step 43 Go to Step 42
37 Replace the thermo relay. Did you complete the replacement?
Go to Step 43
38 Replace the pressure switch. Refer to Heating and
Air Conditioning section.
Did you complete the replacement?
Go to Step 43
39 Replace the electronic thermostat. Refer to Heating
and Air Conditioning section.
Did you complete the replacement?
Go to Step 43
40 Replace the A/C switch. Refer to Heating and Air
Conditioning section.
Did you complete the replacement?
Go to Step 43
41 Replace the blower motor switch. Refer to Heating
and Air Conditioning section.
Did you complete the replacement?
Go to Step 43
42 Important: Replacement ECM must be
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement?
Go to Step 43
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Page 1288 of 6020
6E-254 Engine Control System (4JH1)
Step Action Value(s) Yes No
43 1. Reconnect all previously disconnected fuse,
relay or harness connector(s).
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Turn ON the blower motor switch.
Does the blower motor turn ON and operate
correctly?
Go to Char 1 of 2 Step 4 Refer to Applicable
Diagnostic Chart in Heating & Air Conditioning Section
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Page 1294 of 6020
6E-260 Engine Control System (4JH1)
Checks Action
Engine Mechanical Checks Inspect the engine mechanical for the following conditions. Refer to the Engine
Mechanical section.
• Inspect for poor cylinder compression. Proper compression is more than 2100 kPa
(309 psi).
• Improper mechanical timing (timing gear)
• Improper valve gap
• Broken or weak valve springs
• W orn camshaft lobes
Electrical System Checks Inspect the engine electrical for the following conditions. Refer to the Engine Electrical
section.
• Inspect the glow plug control (preheating) system operation.
• Inspect for slow cranking speed.
• Inspect for weakened batteries.
Rough, Unstable, or Incorrect Idle And Stalling
Checks Action
DEFINITION:Engine runs unevenly at idle. If severe, the engine or vehicle may shake. Engine idle speed may vary in RPM.
Either condition may be severe enough to stall the engine.
Preliminary Checks • Diagnostic System Check - Engine Controls.
• Remove the air cleaner and check for dirt, or for air ducts being plugged or restricted.
Replace as necessary.
• Inspect the Engine Control Module (ECM) and fuel injection pump control unit (PCU)
grounds for being clean, tight, and in their proper locations.
• Inspect that the harness connectors are correctly connected.
• Inspect the fuel type and quality.
• Inspect the scan tool Data List in this section.
• Inspect the Service Bulletins for ECM software updates.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the scan tool Data
List in this section.
• Use the scan tool to compare the Engine Coolant Temperature (ECT) with the Intake Air
Temperature (IAT) and Fuel Temperature (FT) on a cold engine condition. If the
difference among temperature reading is more than 5°C (9°F) on a cold engine, check for
high resistance on the low reference circuit and signal circuit or for a skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT sensor may
indicate a higher than normal intake air temperature if the ignition switch is being ON. FT
sensor is internal to the PCU and it is part of the fuel injection pump assembly.
• Use the scan tool to compare the MAF Sensor parameter with the Desired MAF
parameter. Start the engine and warm up (allow engine coolant temperature to reach at
least 60°C [140°F]). The MAF Sensor parameter must follow the Desired MAF parameter
within 100 mg/strk. If not, inspect the air intake system, EGR system components and
contaminated, skewed or slow MAF sensor.
• Inspect the crankshaft position (CKP) sensor is tight and the flywheel circumference is
not damaged.
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Page 1308 of 6020
6E-274 Engine Control System (4JH1)
Checks Action
Air Intake System Checks Inspect the air intake system for the following conditions.
• Inspect the air cleaner and air intake ducts for a restriction, holes, or leaks.
• Inspect for a restriction or leak in the intercooler.
• Inspect for a restriction in the turbocharger inlet duct.
• Inspect for a restriction or leak in the intake manifold.
• Inspect for a restriction or damage at MAF sensor.
• Inspect for a worn or damaged turbocharger turbine wheel, shaft or compressor
wheel. Refer to turbocharger inspection in the Engine Mechanical section.
Engine Mechanical Checks Inspect the engine mechanical for the following conditions. Refer to the Engine
Mechanical section.
• Inspect for poor cylinder compression. Proper compression is more than 2100 kPa
(309 psi).
• Inspect for incorrect basic engine parts such as camshaft, cylinder head, pistons,
etc.
• Improper mechanical timing
• Improper valve gap
• Broken or weak valve springs
• W orn camshaft lobes
• Inspect for any excessive fuel entering combustion chamber.
• Inspect for coolant entering the combustion chamber.
Electrical System Checks Inspect the engine electrical for the following conditions. Refer to the Engine Electrical
section.
• Inspect the glow plug control (preheating) system operation.
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