HOW DOES THE KNOCK SENSOR WORK ON ECU - Cars & Trucks

The simple answer is NO, they are there to detect engine knock (pinging) caused by to much ignition timing or not enough fuel (engine running lean). If your knock sensor or sensors are not working the ECU will run the engine in a rich (more fuel) and retarded ignition which will cause a small loss of power and the engine will use more fuel.

If you used wiring harness and ECU from car that new engine came from, no problem. Otherwise, could be a problem. Your stock ECU wants a knock sensor input.

Ecu collects data from all sensors. If they don't "add up" it throws the code. Could be corrosion on the connection or connector is off.
Find the knock sensor on the block, check the connection. If a bad connection scrape spade to bright metal both sides reconnect, clear code. Recheck codes. No help must be knock sensor. so must be changed.

Check for back pressure in exhaust before the convertor

The knock sensor is commonly located on the engine block and essentially listens for improper combustion when the engine is running. Engine knock, or spark knock, is the noise created when the combustion process is erratic or abnormal. Code p0330 indicates that the knock sensor has picked up a frequency outside of the factory-set frequency range for the combustion chamber. The computer uses information from the knock sensor to adjust the engine ignition timing to keep combustion within the safe zone of operation. In general, when the knock sensor code is set, the computer will put the engine into limp mode to help prevent engine damage.

ECU= Engine Control Unit [The Cars Computer]

Code 12 Engine revolution signal missing
Code 52 Knock sensor fault
Code 71 EGR system malfunction

service manual.
Code Description Possible Cause
0 ECU / ECU signal No signal to ECU
1 Oxygen sensor circuit Oxygen sensor or circuit, ECU
2 Oxygen sensor circuit Oxygen sensor or circuit, ECU
3 MAP sensor circuit Map sensor circuit
4 CKP sensor / engine speed (RPM) Crank angle sensor or circuit, ECU
sensor
5 MAP sensor circuit MAP sensor or circuit, mechanical
problem
6 ECT sensor circuit ECT sensor or circuit, automatic
transaxle control unit
7 TPS / Angle Sensor TPS sensor or circuit, automatic
transaxle control unit
8 CKP sensor / engine speed (RPM) Crank angle sensor or circuit, ECU
sensor
9 CMP sensor CMP sensor or circuit
10 IAT sensor IAT sensor or circuit
11 Idle Mixture Adjuster Sensor Idle mixture adjuster sensor or
circuit
12 EGR system fault No EGR action, faulty EGR valve
13 BARO sensor circuit BARO sensor or circuit
14 Idle Air Control valve circuit / ECU Open or shorted out ignition signal
circuit / No signal to ECU
15 Ignition Output signal Open or shorted ignition output
signal circuit
16 Fuel Injector Circuit Open or shorted fuel injector
circuit
17 VSS circuit VSS sensor or circuit
18 Ignition Timing Adjuster Open or shorted signal circuit
19 A/T Lock-up control solenoid Open or shorted signal circuit,
Lock-up control solenoid lock-up solenoid
20 Electrical Load Detector / Sensor Electrical load detector or circuit
Honda/Acura
Fault Code Definitions (21 - 59)
Chapter 3 22
Code Description Possible Cause
21 Spool Solenoid Valve Open or shorted signal circuit,
spool solenoid valve
22 Valve Timing Electronic Oil Open or shorted signal circuit,
pressure switch valve timing oil pressure switch
23 Knock sensor circuit Knock sensor or circuit
30 AT / ECU communication signal A AT control unit, ECU
31 AT / ECU communication signal B AT control unit, ECU
35 Traction control / ECU / signal Traction control module, ECU
36 Traction control / ECU / signal Traction control module, ECU
41 Oxygen sensor heater - left side Oxygen sensor / heater or circuit
42 Oxygen sensor heater - right side Oxygen sensor / heater or circuit
43 Fuel Supply system - left side Oxygen sensor or circuit, fuel
system
44 Fuel Supply system - right side Oxygen sensor or circuit, fuel
system
45 Fuel metering - left side Injector control circuit, incorrect
fuel metering
46 Fuel metering - right side Injector control circuit, incorrect
fuel metering
48 Heated oxygen sensor Oxygen sensor or circuit
53 Right Knock Sensor Right knock sensor or circuit
54 CKP sensor 2 CKP sensor 2 or circuit
59 CMP sensor 2 CMP sensor 2 or circuit

I would check the injectors for each cylinder, and check for spark in each cylinder.

If the injectors are not firing in all cylinders, it may be a computer.

If spark occurs in some but not all cylinders, it could be an ignition coil.

DISTRIBUTORLESS IGNITION SYSTEM General Information A distributorless ignition system is used on all 2.2L and 2.5L models. The system consists of a cam and crankshaft angle sensor, knock sensor, two ignition coils, an Electronic Control Unit (ECU) and assorted sensors. The system control features a quick response learning control method that compares data stored in the ECU memory to data received from the sensors. Thus, the ECU constantly provides the optimum ignition timing in relation to output, fuel consumption, exhaust gas and other variables. The ECU receives signals from the airflow sensor, water temperature sensor, crank angle sensor, cam angle sensor, knock sensor and other various indicators to judge the operating condition of the engine. It then selects the optimum ignition timing stored in the memory and immediately transmits a primary current OFF signal to the igniter to control the ignition timing. The ECU also receives signals emitted from the knock sensor. Ignition timing is controlled so that advanced ignition timing is maintained immediately before engine knock occurs. Two ignition coils are used, one for the No. 1 and No. 2 cylinders, and one for the No. 3 and No. 4 cylinders. A simultaneous ignition type is employed for each bank of cylinders. This eliminates the distributor and achieves maintenance free operation. Ignition control under normal conditions is performed by the ECU measuring engine revolutions. Using the data it receives, the ECU decides the ignition timing according to engine operation. Ignition control under starting conditions is set by the ECU at 10°BTDC.

The APC valve regulates boost pressure (via the wastegate) to avoid over-pressurising the engine. It ensures that a safe boost pressure isn't exceeded. Don't run with it disconnected or you risk blowing the engine!

Problem areas can include: knock sensor on the engine block (also poor quality fuel, dirty engine causing knock); engine ECU.

You need to provide more information about when this happens:

hard accelerating? (likely poor quality fuel, dirty plugs/engine causing knock) and general driving similar.

idling? possibly a knock sensor or ECU related problem

What rpm? what boost gauge pressure?

as an outside chance, maybe a sticky wastegate

Saabreur

Well, you have another issue besides a knock sensor problem. A knock sensor code WILL NOT illuminate the check engine light. Check for other codes stored in the ECU. I have seen oxygen sensor issues cause knock sensor issues due to inaccurate fuel delivery resulting in engine ping at all times (causing the ECU to think that the knock sensor is bad because it's reporting ping at all times) - but also had codes for one or more O2 sensors.

Nissan Scope Technician- 10 years with Nissan