Circuit Description
The camshaft position (CMP) sensor indicates the camshaft position so the powertrain control module (PCM) can determine which cylinder is misfiring when a misfire is present. Whenever the PCM receives an intermittent signal from the CMP, then the CMP actrivity counter will increment. In order to set a DTC, the PCM must see a minimum number of resyncs within a maximum time.
Conditions for Setting the DTC
| • | The Engine is running. |
| • | The Cam Sensor activity counter does not increment. |
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate. |
| • | The PCM will record the operating conditions at the time that the diagnostic fails. The Freeze Frame and Failure Records buffers will store this information. |
| • | A history DTC stores. |
Conditions for Clearing the MIL/DTC
| • | The malfunction indicator lamp (MIL) will turn OFF after 3 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | A history DTC will clear after 40 consecutive warm up cycles without a fault. |
| • | Use a scan tool to clear the DTCs. |
Diagnostic Aids
| • | A poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation may cause an intermittent problem. |
| • | Thoroughly check any circuitry, that is suspected as causing the intermittent complaint, proper mating, broken locks, improperly formed or damaged terminals, or physical damage to the wiring harness. |
| • | Whenever the PCM sees less than 15 resyncs in 256 seconds, the counter resets to 0. Anytime a poor connection is present, the cam sensor reference activity counter stops incrementing and the cam sensor resync counter starts to increment. |
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
-
The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
-
This step determines if DTC P0342 is the result of a hard malfunction or an intermittent condition.
-
Determines if the voltage is available to the CMP sensor through the PCM.
-
Determines if the voltage is available to the CMP sensor through the PCM.
-
This step checks for a signal from the CMP sensor. It is necessary to supply B+ to the ignition feed #2 terminal in order for the CMP sensor to have B+ supplied to it. While cranking the engine, the CMP sensor will send a B+ signal and then a ground signal as the reluctor passes the sensor.
-
Replacement PCMs must be reprogrammed and the crankshaft position system variation procedure must be performed. Refer to the latest Isuzu Technical Communication System (ITCS) information for programming procedures and also refer to the Powertrain Control Module (PCM) .
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to | ||
Is the CMP Reference Activity counter incrementing? | -- | |||
3 |
Is the CMP Reference Activity Counter incrementing? | -- | ||
Did the test light illuminate? | -- | |||
Connect a test light to B+ and probe the CMP ground terminal. Did the test light illuminate? | -- | |||
6 | Check for a poor connection or open in the CMP B+ feed circuit and repair as necessary. Was a repair necessary? | -- | ||
Does the DVM display a voltage varying between the specified values? | C1 0V-B+ | |||
8 | Check for a poor connection or an open in the CMP ground circuit and repair as necessary. Was a repair necessary? | -- | ||
9 | Did the DVM display a steady voltage of the specified value? | B+ | ||
10 | Check the CMP signal circuit for a short to B+ and repair as necessary. Was a repair necessary? | -- | ||
11 |
Did the DVM display a voltage greater than the specified value? | 0.5V | ||
12 | Repair the short to ground in the CMP signal circuit. Is the action complete? | -- | -- | |
13 | Check for a poor connection or an open in the CMP signal circuit and repair as necessary. Was a repair necessary? | -- | ||
14 | Replace the Camshaft Position (CMP) sensor. Refer to Camshaft Position Sensor Replacement . Is the action complete? | -- | -- | |
Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | ||
16 |
Does the scan tool indicate that this diagnostic has ran and passed? | -- | ||
17 | Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed? | -- | Go to applicable DTC table | System OK |
