Question about 1997 Dodge Ram 1500 Club Cab

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What does code p1391 mean when failing an emissions test

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  • Master
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Intermittent loss of crankshaft or camshaft position sensor.

Posted on Oct 14, 2009

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  • Dodge Master
  • 85,020 Answers

Symptom:
P1391-INTERMITTENT LOSS OF CMP OR CKP
When Monitored and Set Condition:
P1391-INTERMITTENT LOSS OF CMP OR CKP
When Monitored: Engine running or cranking.
Set Condition: When the failure counter reaches 20 for 2 consecutive trips.
POSSIBLE CAUSES
DAMAGED TONE WHEEL/FLEX PLATE (CRANKSHAFT)
DAMAGED TONE WHEEL/PULSE RING (CAMSHAFT)
INTERMITTENT CMP SIGNAL LOSS WHEN WIRING IS WIGGLED
INTERMITTENT CKP SIGNAL LOSS WHEN WIRING IS WIGGLED
IRREGULAR LAB SCOPE PATTERN OF CKP SIGNAL
IRREGULAR LAB SCOPE PATTERN OF CMP SIGNAL
CAMSHAFT POSITION SENSOR
SENSOR CONNECTOR/WIRING
CRANKSHAFT POSITION SENSOR
TEST ACTION APPLICABILITY
1 Turn ignition on.
With the DRB, read the DTC’s.
Is the Global Good Trip Counter displayed and equal to zero for P1391?
All
Yes ® Go To 2
No ® Go To 13
2 Turn ignition off.
With the DRB lab scope, backprobe the CMP signal circuit at the CMP sensor
connector using Miller special tool #6801.
Warning: Keep clear of the engine’s moving parts.
Start the engine.
Observe the CMP sensor voltage pattern on the lab scope screen.
Are there any signals missing?
All
Yes ® Go To 3
No ® Go To 6
230
DRIVEABILITY
Turn ignition off.
Visually inspect the related wire harness connectors. Look for broken, bent,
pushed out, or corroded terminals.
Visually inspect the related wiring harness. Look for any chafed, pierced,
pinched, or partially broken wires.
Note: Make sure the Camshaft Position Sensor and/or the Crankshaft
Position Sensor is tight.
Note: Refer to any technical service bulletins that may apply.
Were any problems found?
All
Yes ® Repair as necessary.
Perform the Powertrain Verification Test - Ver 5
No ® Go To 4
4 Turn ignition off.
Disconnect and remove the camshaft position sensor.
Inspect the tone wheel/pulse ring for looseness and/or physical damage.
Is the tone wheel/pulse ring free from defects?
All
Yes ® Go To 5
No ® Repair/replace tone wheel/pulse ring as necessary.
5 If there are no possible causes remaining, replace the Camshaft Position Sensor.
View repair options.
All
Repair
Replace the Camshaft Position Sensor.
Perform the Powertrain Verification Test - Ver 5
6 Turn ignition off.
With the DRB lab scope, backprobe the CKP signal circuit at the CKP sensor
connector using Miller special tool #6801.
Warning: Keep clear of the engine’s moving parts.
Start the engine.
Observe the CKP sensor voltage pattern on the lab scope screen.
Are there any signals missing?
All
Yes ® Go To 7
No ® Go To 10
7 Turn ignition off.
Visually inspect the related wire harness connectors. Look for broken, bent,
pushed out, or corroded terminals.
Visually inspect the related wiring harness. Look for any chafed, pierced,
pinched, or partially broken wires.
Note: Make sure the Camshaft Position Sensor and/or the Crankshaft
Position Sensor is tight.
Note: Refer to any technical service bulletins that may apply.
Were any problems found?
All
Yes ® Repair as necessary.
Perform the Powertrain Verification Test - Ver 5
No ® Go To 8
231
DRIVEABILITY
TEST ACTION APPLICABILITY
8 Turn ignition off.
Disconnect and remove the crankshaft position sensor.
Inspect the tone wheel/flexplate slots for damage, foreign material, or excessive
movement.
Is the tone wheel/flexplate free from defects?
All
Yes ® Go To 9
No ® Repair/replace tone wheel/flex plate as necessary.
9 If there are no possible causes remaining, replace the Crankshaft Position Sensor.
View repair options.
All
Repair
Replace the Crankshaft Position Sensor.
Perform the Powertrain Verification Test - Ver 5
10 Turn ignition off.
Visually inspect the related wire harness connectors. Look for broken, bent,
pushed out, or corroded terminals.
Visually inspect the related wiring harness. Look for any chafed, pierced,
pinched, or partially broken wires.
Note: Make sure the Camshaft Position Sensor and/or the Crankshaft
Position Sensor is tight.
Note: Refer to any technical service bulletins that may apply.
Were any problems found?
All
Yes ® Repair as necessary.
Perform the Powertrain Verification Test - Ver 5
No ® Go To 11
11 Turn ignition off.
With the DRB lab scope, backprobe the CMP signal circuit at the PCM connector
using Miller special tool #6801.
Warning: Keep clear of the engine’s moving parts.
Start the engine.
Observe the lab scope screen while wiggling the wiring harness and connectors
related to the CMP sensor.
Were there any irregularities in the lab scope pattern when the wiggle test was
conducted?
All
Yes ® Note where wiggling caused a missing CMP sensor signal. Repair
CMP sensor wiring as necessary.
Perform the Powertrain Verification Test - Ver 5
No ® Go To 12
232
DRIVEABILITY
P1391-INTERMITTENT LOSS OF CMP OR CKP — Continued
TEST ACTION APPLICABILITY
12 Turn ignition off.
With the DRB lab scope, backprobe the CKP signal circuit at the PCM connector
using Miller special tool #6801.
Warning: Keep clear of the engine’s moving parts.
Start the engine.
Observe the lab scope screen while wiggling the wiring harness and connectors
related to the CKP sensor.
Were there any irregularities in the lab scope pattern when the wiggle test was
conducted?
All
Yes ® Note where wiggling caused a missing CKP sensor signal. Repair
CKP sensor wiring as necessary.
Perform the Powertrain Verification Test - Ver 5
No ® Test Complete.
13 Turn ignition off.
Connect the DRBIII lab scope to the CMP signal circuit. For best results, backprobe
at the PCM using Miller special tool #6801.
Warning: Keep clear of the engine’s moving parts.
Start the engine.
Observe the lab scope screen while wiggling the wiring harness and connectors.
Were there any irregularities in the lab scope pattern?
All
Yes ® Check harness and connectors carefully. If OK, replace the
Camshaft Position Sensor.
Perform the Powertrain Verification Test - Ver 5
No ® Go To 14
14 Turn ignition off.
Visually inspect the related wire harness connectors. Look for broken, bent,
pushed out, or corroded terminals.
Visually inspect the related wiring harness. Look for any chafed, pierced,
pinched, or partially broken wires.
Note: Make sure the Camshaft Position Sensor and/or the Crankshaft
Position Sensor is tight.
Note: Refer to any technical service bulletins that may apply.
Were any problems found?
All
Yes ® Repair as necessary.
Perform the Powertrain Verification Test - Ver 5
No ® Go To 15
15 Turn ignition off.
Connect the DRBIII lab scope to the CKP signal circuit. For best results, backprobe
at the PCM using Miller special tool #6801.
Warning: Keep clear of the engine’s moving parts.
Start the engine.
Observe the lab scope screen while wiggling the wiring harness and connectors.
Were there any irregularities in the lab scope pattern?
All
Yes ® Check harness and connectors carefully. If OK, replace the
Crankshaft Position Sensor.
Perform the Powertrain Verification Test - Ver 5
No ® Test Complete.
233
DRIVEABILITY

Posted on Oct 14, 2009

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  • Master
  • 407 Answers

You sure that is the correct code

Posted on Oct 14, 2009

2 Suggested Answers

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  • 2 Answers

SOURCE:

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Posted on Jan 02, 2017

  • 1757 Answers

SOURCE: P0320 & P1391 OBD codes displayed.

P 0320 = No Crank Reference Signal to PCM. No Crank (shaft position) reference signal detected during engine cranking (starting).
P 1391 =Intermittent Loss of either Camshaft Position Sensor or Crankshaft Position Sensor.
Hav you attemtped the "3-Key-Ons" method to see these codes on your digital Odometer (assuming you have one) Turn the Key from Off to On (not start) three (3) times. On the third (3rd) time leave the Key in the "On" position (not start). Look at your Dogotal Odometer (if so equipped). The Codes, one at a time should appear. The Last Code will be "P donE".
If te engine is performing without problems: disconnect the negative side of the Battery and wait at least 5 to 30 minutes. Reconnect the Battery. Re-preform the 3-Key-On's and see if and Codes are now showing.
If you start having Start or Running problems becoming more and more frequent: consider replacing the Crankshaft Position Sensor. If this sensor "fails" you may not get any fire to anything, as this is the signal that is necessary for the PCM to initiate the Firing Sequence. The PCM will not send a signal to even the Ignition Coil to begin.

Posted on Jan 08, 2010

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Hav you attemtped the "3-Key-Ons" method to see these codes on your digital Odometer (assuming you have one) Turn the Key from Off to On (not start) three (3) times. On the third (3rd) time leave the Key in the "On" position (not start). Look at your Dogotal Odometer (if so equipped). The Codes, one at a time should appear. The Last Code will be "P donE".
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