Description of SID 21 – Crankshaft Position Sensor Outside of Normal Operating Conditions
SID 021 indicates that the PLD-MR control unit has detected the Crankshaft Position (CKP) sensor operating outside of normal operating conditions.
The diagnostic condition is typically:
- CKP Sensor Signal Voltage Too Low (021 01)
- CKP Sensor Open Circuit (021 03)
- CKP Sensor Short to Ground (021 04)
- No Match of Camshaft and Crankshaft Signals (021 07)
- CKP Sensor Time Out (021 08)
- CKP Sensor Pins Swapped (021 14)
See Figure “Sensor Location on MBE 6-Cylinder Engine” for sensor locations on the typical MBE 6-cylinder engine.
Note: Sensor locations are similar on the 4-cylinder engine. The Engine Oil Level (EOL) sensor, if used, is located at the bottom of the oil pan.
Note: * The Baro sensor is integrated into the PLD-MR unit.
| 1. Engine Oil Pressure (EOP) Sensor | 5. Barometric Pressure (Baro) Sensor * |
| 2. Engine Coolant Temperature (ECT) Sensor | 6. Camshaft Position (CMP) Sensor – on Cylinder Block |
| 3. Intake Manifold Pressure (IMP) Sensor | 7. CKP Sensor – on Timing Case |
| 4. Supply Fuel Temperature (SFT) Sensor | |
Figure 1. Sensor Location on MBE 6-Cylinder Engine
The engine harness is delivered to the factory with the engine sensors and the PLD-MR already connected. See Figure “Typical On-Highway Six-Cylinder Engine Harness” for a typical six-cylinder engine harness. Engine harness sensor pin locations are listed in Table “Selected Harness Pin Locations” .
Figure 2. Typical On-Highway Six-Cylinder Engine Harness
| Pin | Wire Color | Signal Type | Function | Connector | ||||
| 6- Cylinder | 4- Cylinder | |||||||
| 1 | Blk/Yel | Blk/Yel | Sensor Return | CMP Sensor (-) |
 Front Looking into the Pins |
|||
| 2 | Blk/Viol | Blk/Viol | Sensor Return | CKP Sensor (-) | ||||
| 19 | Brn/Viol | Brn/Viol | Frequency Input | CKP Sensor (+) | ||||
| 20 | Brn/Yel | Brn/Yel | Frequency Input | CMP Sensor (+) | ||||
The CKP sensor and its bracket are located on the flywheel housing. See Figure “Crankshaft Position Sensor and Bracket Location” . In most cases the CKP sensor bracket is replaced only when the flywheel housing is replaced.
| 1. CKP Sensor Bracket | 4. CKP Sensor |
| 2. Shear Bolt (2 Qty.) | 5. Reference Hole on Flywheel Edge |
| 3. Spring Bushing | |
Figure 3. Crankshaft Position Sensor and Bracket Location
