DTC P0327: KNOCK SENSOR CIRCUIT Isuzu Rodeo II

Note. If an engine knock can be heard, repair engine mechanical problem before proceeding with circuit test.

Circuit Description

Knock Sensor (KS) is used to detect engine detonation, allowing PCM to retard Ignition Control (IC) spark timing based on KS signal being received. KS produces an AC signal so that under a no knock condition signal on KS circuit measures about 0.007 volts AC. KS signals amplitude and frequency depend on amount of knock being experienced. PCM monitors KS signal and can diagnose KS and circuitry. Conditions for setting DTC

1. Engine running for at least 30 seconds.
2. TP sensor is more than 5 percent.
3. Engine Coolant Temperature (ECT) sensor is more than 140°F (60°C).
4. Engine speed is between 2000 and 4000 RPM.
5. Knock Sensor (KS) signal voltage is less than 0.02 volts, or more than 4.8 volts.
6. All conditions are present for more than 15 seconds.

Diagnostic Aids

If DTC can not be duplicated, reviewing scan tool FAILURE RECORDS data can be useful in determining mileage and frequency of DTC occurrence.

1. Perform «ON-BOARD DIAGNOSTIC II SYSTEM CHECK»(ref-97343-S01178100682001050100000) under SELF-DIAGNOSTIC SYSTEM. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. Operate vehicle under conditions to allow DTC to set. Using scan tool, monitor SPECIFIC DTC parameter until DTC P0327 test runs. If scan tool indicates DTC P0327 FAILED THIS IGNITION, go to step 4 . If scan tool display is not as specified, go to next step.
3. With ignition on and engine off, review and record FAILURE RECORDS for DTC P0327. Operate vehicle within FAILURE RECORDS conditions. Using scan tool, monitor SPECIFIC DTC parameter until DTC P0327 test runs. If scan tool indicates DTC P0327 FAILED THIS IGNITION, go to next step. If scan tool display is not as specified, check for an intermittent problem. See «DIAGNOSTIC AIDS»(ref-97343-S29348417492001050100000) .
4. Using test light connected to positive battery terminal, check for open circuit to ground in Knock Sensor (KS) shielded coaxial wire on PCM side (Black/Blue wire). Repair as necessary. Retest system. If KS shielded coaxial wire is okay, go to next step.
5. Ensure ignition is off. Disconnect PCM harness connectors. Check KS signal circuit for poor connection at PCM. Repair as necessary. Retest system. If connections are okay, go to next step.
6. Using a DVOM, check KS signal circuit between PCM harness connector and KS harness connector for an open, short to voltage or short to ground. Repair as necessary. Retest system. If wire is okay, go to next step.
7. Reconnect KS harness connector. Measure resistance of KS between signal circuit at PCM harness connector and engine block. If resistance is about 100 k/ohms, go to next step. If resistance is not about 100 k/ohms, replace KS. Retest system.
8. Set voltmeter to AC scale. Connect voltmeter between ground and KS signal circuit at PCM harness connector. Measure voltage produced by KS while tapping on engine lift bracket. If an AC voltage is produced, replace and reprogram PCM. See «EEPROM PROGRAMMING PROCEDURE»(ref-97343-S42360493802001050100000) under PROGRAMMING. If no voltage is produced, replace KS. Retest system.

58X reference signal is produced by Crankshaft Position (CKP) sensor. During one crankshaft revolution, 58 crankshaft reference pulses will be produced. PCM uses 58X reference signal to calculate engine RPM and crankshaft position. PCM constantly monitors number of pulses on 58X reference circuit and compares them to number of Camshaft Position (CMP) sensor signal pulses being received. If PCM receives an incorrect number of pulses on 58X reference circuit, DTC P0336 is set. Conditions for setting DTC

1. Engine is running.
2. Extra or missing pulse is detected between consecutive 58X reference pulses.
3. Above condition is detected in 10 of 100 crankshaft rotations.

An intermittent may be caused by a poor connection, rubbed-through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. Connect voltmeter to 58X reference circuit and wiggle harness and connectors. A change in voltage will indicate area of problem. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.