Manual de instrucciones de Toyota P0325

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DI–71
DIAGNOSTICS – ENGINE
DI38A–03
DTC P0325 Knock Sensor 1 Circuit Malfunction
CIRCUIT DESCRIPTION
The knock sensor is fitted to the cylinder block to detect engine knocking. This sensor contains a piezoelec-
tric element which generates a voltage when it becomes deformed, which occurs when the cylinder block
vibrates due to knocking. If engine knocking occurs, ignition timing is retarded to suppress it.
DTC No. DTC Detecting Condition Trouble Area
Open or short in knock sensor 1 circuit
No

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DI–72 DIAGNOSTICS – ENGINE 1 Check continuity between terminal KNK of ECM connector and body ground. PREPARATION: LOCK (a) Remove the ECM cover. (b) Disconnect the E5 connector of the ECM. CHECK: Measure resistance between terminal KNK of the ECM connec- tor and body ground. OK: Resistance: 1 MW or higher KNK1 A09094 A09086 OK Go to step 3. NG 2 Check knock sensor 1 (See page SF–68). NG Replace knock sensor 1. OK 3 Check for open and short in harness and connector between ECM and knock sensor 1

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DI–73 DIAGNOSTICS – ENGINE 4 Does malfunction disappear when a good knock sensor 1 is installed? YES Replace knock sensor 1. NO Check and replace ECM (See page IN–30). Reference: INSPECTION USING OSCILLOSCOPE KNK signal waveform With the engine racing (4,000 rpm) measure between ter- 0.5V/ minal KNK of the ECM connector and body ground. Division HINT: The correct waveforms are as shown. 0V Spread the time on the horizontal axis, and confirm that period of the wave is 80 m sec. 5 m sec.