KNOCK CONTROL SYSTEM CHECK
Check the knock sensor circuit if diagnostic trouble code, No. P0326, P0327 or P0328 is shown.
Refer to DIAGNOSTIC TROUBLE CODE CHART .
IGNITION COIL CHECK
Required Special Tool
MB991958: Scan Tool (M.U.T-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A
| CAUTION | To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958. |
Note. It is impossible to carry out an easy check using a circuit tester because a diode and so on are integrated into the inside circuit of this ignition coil. Accordingly, check the ignition coil in the following procedure.
Scheme 23
- Make sure the diagnosis codes are not stored using scan tool MB991958. If stored, record the code No. Carry out the troubleshooting for the stored codes and solve the problems even if not related to the ignition.
- Disconnect the injector connectors on all of the cylinders.
- Disconnect the ignition coil connector.
- Remove the ignition coil and install a good spark plug to the ignition coil.
- Connect the ignition coil connector.
- Ground the side electrode of the spark plug and crank the engine.
- Check that spark is produced between the electrodes of the spark plug.
- If the spark plug has weak spark or no spark, carry out the same check using a good ignition coil. If there is strong spark on this check with a good ignition coil, it becomes clear there is a problem with the ignition coil. Replace the ignition coil with a new one. If there is no spark on this check with a good ignition coil, there is probably a problem with the ignition circuit. Check the ignition circuit.
- Using scan tool MB991958, make sure whether the diagnosis codes are stored due to the check, or not. Except the codes stored in Step 1 , clear the codes all together if they are present. And then, carry out the troubleshooting about the codes recorded. CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
- Disconnect scan tool MB991958 to the data link connector.
Scheme 24
Scheme 25
- Remove the spark plug and connect to the ignition coil.
- Ground the spark plug outer electrode (body), and crank the engine. Check that there is an electrical discharge between the electrodes at this time.
SPARK PLUG CHECK AND CLEANING
Required Special Tool
MB992273: Spark Plug Brush
| CAUTION | Never attempt to adjust the gap of the iridium plug. Do not attempt to clean the iridium plug using a wire brush because it may result in damage to the electrode. When the iridium plug is cleaned, use a plug cleaner, sand blast type, or special tool Spark Plug Brush (MB992273). |
Note. Obey the maintenance interval of the relevant vehicle for the spark plug replacement. If the plug gap and insulation resistance are normal, check the plug condition and clean if necessary.
SPARK PLUG GAP CHECK
Check the plug gap with the wire type plug gauge. Replace it if the limit is exceeded.
Standard value: 0.5 - 0.6 mm (0.020 - 0.023 inch)
Limit: 0.8 mm (0.031 inch)
Scheme 26
Scheme 27
- Measure the insulation resistance of the spark plug. If the insulation resistance of the spark plug is under the limited value, clean the spark plug (Refer to «SPARK PLUG CLEANING»(ref-592703-S36578991562014011000000) ).
- After cleaning, measure the insulation resistance again. Replace the plug unless it is within the limited value. Limit: Minimum 10 Mohms
SPARK PLUG CLEANING
Note. Using a sand blast type plug cleaner, is recommended for the spark plug cleaning.
< When a sand blast type plug cleaner is used>
Cleaning must be carried out within 20 seconds to protect the electrode.
< When special tool MB992273 is used>
Scheme 28
- Sufficiently apply the brake cleaner to the plug end. NOTE: Repeatedly applying the brake cleaner is acceptable during the cleaning.
- Using special tool MB992273, intensively clean the electrode for 1 to 2 minutes. NOTE: Even if using strong force, the electrode is not damaged. NOTE: In case of insufficient cleaning, it is permissible to take longer than 2 minutes for cleaning.
- After the cleaning, sufficiently remove and then dry both of the carbon and the brake cleaner on the plug, using a waste cloth or air blowing.
CAMSHAFT POSITION SENSOR CHECK
Refer to DTC P0340: INTAKE CAMSHAFT POSITION SENSOR CIRCUIT .
CRANKSHAFT POSITION SENSOR CHECK
Refer to DTC P0335: CRANKSHAFT POSITION SENSOR CIRCUIT .